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diff --git a/src/main.py b/src/main.py
new file mode 100644
index 0000000..1524dbd
--- /dev/null
+++ b/src/main.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+"""
+数学练习系统 - 面向小学、初中和高中学生的数学题目练习应用
+支持用户注册、登录、密码管理、题目生成和答题功能
+"""
+
+import tkinter as tk
+from main_app import MathQuizApp
+
+
+def main():
+    """
+    主函数
+    """
+    root = tk.Tk()
+    app = MathQuizApp(root)
+    root.mainloop()
+
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file
diff --git a/src/main_app.py b/src/main_app.py
new file mode 100644
index 0000000..99591b2
--- /dev/null
+++ b/src/main_app.py
@@ -0,0 +1,775 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+"""
+主应用模块
+"""
+
+import tkinter as tk
+from tkinter import messagebox, ttk
+import random
+from typing import List, Optional
+
+from user_manager import UserManager
+from question_bank import QuestionBank
+from quiz import Quiz
+from question_generator import Expression
+
+
+class MathQuizApp:
+    """
+    数学测验应用程序主类
+    """
+
+    def __init__(self, root: tk.Tk):
+        """
+        初始化应用程序
+        
+        @param root: Tk根窗口
+        """
+        self.root = root
+        self.root.title("数学练习系统")
+        self.root.geometry("700x600")
+        self.root.resizable(True, True)
+        self.root.configure(bg="#f0f0f0")
+        
+        # 初始化系统组件
+        self.user_manager = UserManager()
+        self.question_bank = QuestionBank()
+        
+        # 设置样式
+        self.setup_styles()
+        
+        # 创建不同的界面框架
+        self.login_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.register_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.set_password_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.main_menu_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.quiz_setup_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.quiz_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.result_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.change_password_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.delete_account_frame = tk.Frame(self.root, bg="#f0f0f0")  # 添加删除账户框架
+        
+        # 初始化应用状态
+        self.current_quiz: Optional[Quiz] = None
+        self.current_level = ""
+        self.question_count = 0
+        
+        # 创建界面
+        self.create_widgets()
+        self.show_login_frame()
+
+    def setup_styles(self):
+        """
+        设置界面样式
+        """
+        self.title_font = ("Arial", 20, "bold")
+        self.header_font = ("Arial", 16, "bold")
+        self.normal_font = ("Arial", 12)
+        self.button_font = ("Arial", 11, "bold")
+        
+        # 定义颜色方案
+        self.primary_color = "#4a6fa5"
+        self.secondary_color = "#6b8cbc"
+        self.accent_color = "#ff6b6b"
+        self.success_color = "#4caf50"
+        self.warning_color = "#ffc107"
+        self.danger_color = "#f44336"
+        self.light_bg = "#f8f9fa"
+        self.dark_text = "#333333"
+
+    def create_widgets(self):
+        """
+        创建界面组件
+        """
+        # 创建不同的界面框架
+        self.login_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.register_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.set_password_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.main_menu_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.quiz_setup_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.quiz_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.result_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.change_password_frame = tk.Frame(self.root, bg="#f0f0f0")
+        self.delete_account_frame = tk.Frame(self.root, bg="#f0f0f0")  # 添加删除账户框架
+
+    def show_frame(self, frame: tk.Frame):
+        """
+        显示指定的界面框架
+        
+        @param frame: 要显示的框架
+        """
+        # 隐藏所有框架
+        for f in [self.login_frame, self.register_frame, self.set_password_frame,
+                  self.main_menu_frame, self.quiz_setup_frame, self.quiz_frame,
+                  self.result_frame, self.change_password_frame, self.delete_account_frame]:
+            f.pack_forget()
+        
+        # 显示指定框架
+        frame.pack(fill="both", expand=True)
+
+    def show_login_frame(self):
+        """
+        显示登录界面
+        """
+        # 清除之前的内容
+        for widget in self.login_frame.winfo_children():
+            widget.destroy()
+        
+        # 创建登录界面
+        main_frame = tk.Frame(self.login_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=50, padx=50, fill="both", expand=True)
+        
+        title_frame = tk.Frame(main_frame, bg=self.primary_color)
+        title_frame.pack(fill="x", pady=(0, 30))
+        tk.Label(title_frame, text="用户登录", font=self.title_font, bg=self.primary_color, fg="white").pack(pady=20)
+        
+        form_frame = tk.Frame(main_frame, bg="#ffffff")
+        form_frame.pack(pady=10)
+        
+        tk.Label(form_frame, text="用户名:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.login_email_entry = tk.Entry(form_frame, width=30, font=self.normal_font, relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.login_email_entry.pack(pady=5)
+        
+        tk.Label(form_frame, text="密码:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.login_password_entry = tk.Entry(form_frame, width=30, font=self.normal_font, show="*", relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.login_password_entry.pack(pady=5)
+        
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=20)
+        
+        tk.Button(button_frame, text="登录", command=self.login, width=20, bg=self.primary_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=10)
+        tk.Button(button_frame, text="注册新用户", command=self.show_register_frame, width=20, bg=self.secondary_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=5)
+        tk.Button(button_frame, text="注销账户", command=self.show_delete_account_frame, width=20, bg=self.danger_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=5)
+        
+        self.show_frame(self.login_frame)
+
+    def login(self):
+        """
+        处理登录逻辑
+        """
+        username = self.login_email_entry.get().strip()
+        password = self.login_password_entry.get()
+        
+        if not username or not password:
+            messagebox.showerror("错误", "请输入用户名和密码")
+            return
+        
+        if self.user_manager.login(username, password):
+            messagebox.showinfo("成功", "登录成功")
+            self.show_main_menu_frame()
+        # 错误信息在user_manager.login中已经显示
+
+    def show_register_frame(self):
+        """
+        显示注册界面
+        """
+        # 清除之前的内容
+        for widget in self.register_frame.winfo_children():
+            widget.destroy()
+        
+        # 创建注册界面
+        main_frame = tk.Frame(self.register_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=30, padx=50, fill="both", expand=True)
+        
+        title_frame = tk.Frame(main_frame, bg=self.primary_color)
+        title_frame.pack(fill="x", pady=(0, 20))
+        tk.Label(title_frame, text="用户注册", font=self.title_font, bg=self.primary_color, fg="white").pack(pady=20)
+        
+        form_frame = tk.Frame(main_frame, bg="#ffffff")
+        form_frame.pack(pady=10)
+        
+        tk.Label(form_frame, text="用户名:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.register_username_entry = tk.Entry(form_frame, width=30, font=self.normal_font, relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.register_username_entry.pack(pady=5)
+        
+        tk.Label(form_frame, text="邮箱:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.register_email_entry = tk.Entry(form_frame, width=30, font=self.normal_font, relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.register_email_entry.pack(pady=5)
+        
+        tk.Button(form_frame, text="获取注册码", command=self.send_registration_code, width=20, bg=self.primary_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=10)
+        
+        tk.Label(form_frame, text="注册码:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.registration_code_entry = tk.Entry(form_frame, width=30, font=self.normal_font, relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.registration_code_entry.pack(pady=5)
+        
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=20)
+        
+        tk.Button(button_frame, text="验证注册码", command=self.verify_registration_code, width=20, bg=self.success_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=10)
+        tk.Button(button_frame, text="返回登录", command=self.show_login_frame, width=20, bg="#cccccc", fg=self.dark_text,
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=5)
+        
+        self.show_frame(self.register_frame)
+
+    def send_registration_code(self):
+        """
+        发送注册码
+        """
+        username = self.register_username_entry.get().strip()
+        email = self.register_email_entry.get().strip()
+        
+        if not username or not email:
+            messagebox.showerror("错误", "请输入用户名和邮箱")
+            return
+        
+        if self.user_manager.register_user(email, username):
+            messagebox.showinfo("成功", "注册码已发送，请查收")
+
+    def verify_registration_code(self):
+        """
+        验证注册码
+        """
+        email = self.register_email_entry.get().strip()
+        code = self.registration_code_entry.get().strip()
+        
+        if not email or not code:
+            messagebox.showerror("错误", "请输入邮箱和注册码")
+            return
+        
+        if self.user_manager.verify_registration_code(email, code):
+            messagebox.showinfo("成功", "注册码验证成功，请设置密码")
+            self.show_set_password_frame(email)
+
+    def show_set_password_frame(self, email: str):
+        """
+        显示设置密码界面
+        
+        @param email: 用户邮箱
+        """
+        # 清除之前的内容
+        for widget in self.set_password_frame.winfo_children():
+            widget.destroy()
+        
+        # 创建设置密码界面
+        main_frame = tk.Frame(self.set_password_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=30, padx=50, fill="both", expand=True)
+        
+        title_frame = tk.Frame(main_frame, bg=self.primary_color)
+        title_frame.pack(fill="x", pady=(0, 20))
+        tk.Label(title_frame, text="设置密码", font=self.title_font, bg=self.primary_color, fg="white").pack(pady=20)
+        
+        form_frame = tk.Frame(main_frame, bg="#ffffff")
+        form_frame.pack(pady=10)
+        
+        tk.Label(form_frame, text="邮箱: " + email, font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        
+        tk.Label(form_frame, text="密码:", font=self.normal_font, bg="#ffffff", fg=self.primary_color).pack(pady=(10, 5), anchor="w")
+        tk.Label(form_frame, text="（6-10位，必须包含大小写字母和数字）", font=("Arial", 10), bg="#ffffff", fg="gray").pack(pady=5, anchor="w")
+        self.set_password_entry = tk.Entry(form_frame, width=30, font=self.normal_font, show="*", relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.set_password_entry.pack(pady=5)
+        
+        tk.Label(form_frame, text="确认密码:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.confirm_password_entry = tk.Entry(form_frame, width=30, font=self.normal_font, show="*", relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.confirm_password_entry.pack(pady=5)
+        
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=20)
+        
+        tk.Button(button_frame, text="设置密码", command=lambda: self.set_password(email), width=20, bg=self.success_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=10)
+        tk.Button(button_frame, text="返回登录", command=self.show_login_frame, width=20, bg="#cccccc", fg=self.dark_text,
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=5)
+        
+        self.show_frame(self.set_password_frame)
+
+    def set_password(self, email: str):
+        """
+        设置密码
+        
+        @param email: 用户邮箱
+        """
+        password = self.set_password_entry.get()
+        confirm_password = self.confirm_password_entry.get()
+        
+        if not password or not confirm_password:
+            messagebox.showerror("错误", "请输入密码和确认密码")
+            return
+        
+        if password != confirm_password:
+            messagebox.showerror("错误", "两次输入的密码不一致")
+            return
+        
+        if self.user_manager.set_password(email, password):
+            messagebox.showinfo("成功", "密码设置成功，请登录")
+            self.show_login_frame()
+
+    def show_main_menu_frame(self):
+        """
+        显示主菜单界面
+        """
+        # 清除之前的内容
+        for widget in self.main_menu_frame.winfo_children():
+            widget.destroy()
+        
+        # 创建主菜单界面
+        main_frame = tk.Frame(self.main_menu_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=30, padx=50, fill="both", expand=True)
+        
+        title_frame = tk.Frame(main_frame, bg=self.primary_color)
+        title_frame.pack(fill="x", pady=(0, 20))
+        tk.Label(title_frame, text="主菜单", font=self.title_font, bg=self.primary_color, fg="white").pack(pady=20)
+        
+        user_email = self.user_manager.current_user.email if self.user_manager.current_user else "未知用户"
+        tk.Label(main_frame, text=f"欢迎, {user_email}!", font=self.header_font, bg="#ffffff").pack(pady=10)
+        
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=20)
+        
+        tk.Button(button_frame, text="小学题目", command=lambda: self.show_quiz_setup_frame("elementary"), 
+                  width=20, height=2, bg="#4CAF50", fg="white", font=self.button_font, relief=tk.FLAT, bd=0).pack(pady=10)
+        tk.Button(button_frame, text="初中题目", command=lambda: self.show_quiz_setup_frame("middle"), 
+                  width=20, height=2, bg="#2196F3", fg="white", font=self.button_font, relief=tk.FLAT, bd=0).pack(pady=10)
+        tk.Button(button_frame, text="高中题目", command=lambda: self.show_quiz_setup_frame("high"), 
+                  width=20, height=2, bg="#FF9800", fg="white", font=self.button_font, relief=tk.FLAT, bd=0).pack(pady=10)
+        
+        tk.Button(button_frame, text="修改密码", command=self.show_change_password_frame, 
+                  width=20, bg=self.secondary_color, fg="white", font=self.button_font, relief=tk.FLAT, bd=0, pady=5).pack(pady=10)
+        tk.Button(button_frame, text="退出登录", command=self.logout, width=20, bg=self.danger_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, pady=5).pack(pady=5)
+        
+        self.show_frame(self.main_menu_frame)
+
+    def show_quiz_setup_frame(self, level: str):
+        """
+        显示测验设置界面
+        
+        @param level: 题目难度
+        """
+        self.current_level = level
+        
+        # 清除之前的内容
+        for widget in self.quiz_setup_frame.winfo_children():
+            widget.destroy()
+        
+        # 创建测验设置界面
+        main_frame = tk.Frame(self.quiz_setup_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=30, padx=50, fill="both", expand=True)
+        
+        level_names = {"elementary": "小学", "middle": "初中", "high": "高中"}
+        level_colors = {"elementary": "#4CAF50", "middle": "#2196F3", "high": "#FF9800"}
+        
+        title_frame = tk.Frame(main_frame, bg=level_colors[level])
+        title_frame.pack(fill="x", pady=(0, 20))
+        tk.Label(title_frame, text=f"{level_names[level]}数学题目", font=self.title_font, bg=level_colors[level], fg="white").pack(pady=20)
+        
+        form_frame = tk.Frame(main_frame, bg="#ffffff")
+        form_frame.pack(pady=20)
+        
+        tk.Label(form_frame, text="请输入题目数量 (1-20):", font=self.normal_font, bg="#ffffff").pack(pady=10)
+        self.question_count_entry = tk.Entry(form_frame, width=20, font=self.normal_font, justify="center", relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.question_count_entry.pack(pady=5)
+        self.question_count_entry.insert(0, "10")  # 默认10题
+        
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=20)
+        
+        tk.Button(button_frame, text="开始答题", command=self.start_quiz, width=20, bg=self.success_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=10)
+        tk.Button(button_frame, text="返回主菜单", command=self.show_main_menu_frame, width=20, bg="#cccccc", fg=self.dark_text,
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=5)
+        
+        self.show_frame(self.quiz_setup_frame)
+
+    def start_quiz(self):
+        """
+        开始测验
+        """
+        try:
+            count = int(self.question_count_entry.get())
+            if not (1 <= count <= 20):
+                messagebox.showerror("错误", "题目数量必须在1-20之间")
+                return
+        except ValueError:
+            messagebox.showerror("错误", "请输入有效的数字")
+            return
+        
+        self.question_count = count
+        
+        # 生成题目
+        try:
+            questions = self.question_bank.generate_questions(self.current_level, self.question_count)
+            self.current_quiz = Quiz(questions)
+            self.show_quiz_frame()
+        except Exception as e:
+            messagebox.showerror("错误", f"生成题目时出错: {str(e)}")
+
+    def show_quiz_frame(self):
+        """
+        显示答题界面
+        """
+        if not self.current_quiz:
+            return
+        
+        # 清除之前的内容
+        for widget in self.quiz_frame.winfo_children():
+            widget.destroy()
+        
+        # 创建答题界面
+        current_question = self.current_quiz.get_current_question()
+        if not current_question:
+            return
+        
+        main_frame = tk.Frame(self.quiz_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=20, padx=30, fill="both", expand=True)
+        
+        # 显示题目进度
+        progress = f"题目 {self.current_quiz.current_question_index + 1}/{len(self.current_quiz.questions)}"
+        progress_frame = tk.Frame(main_frame, bg=self.primary_color)
+        progress_frame.pack(fill="x", pady=(0, 20))
+        tk.Label(progress_frame, text=progress, font=self.header_font, bg=self.primary_color, fg="white").pack(pady=10)
+        
+        # 显示题目
+        question_frame = tk.Frame(main_frame, bg="#ffffff")
+        question_frame.pack(pady=10)
+        
+        tk.Label(question_frame, text="题目:", font=self.header_font, bg="#ffffff").pack(pady=(10, 5))
+        question_text = str(current_question)
+        tk.Label(question_frame, text=question_text, font=("Arial", 16, "bold"), bg="#ffffff", wraplength=500).pack(pady=10)
+        
+        # 计算选项
+        options = self.generate_options(current_question.answer)
+        
+        # 显示选项
+        tk.Label(main_frame, text="请选择答案:", font=self.normal_font, bg="#ffffff").pack(pady=(20, 10))
+        
+        self.answer_var = tk.StringVar()
+        self.answer_var.set(" ")  # 明确设置初始值为空字符串，确保不选中任何选项
+        
+        options_frame = tk.Frame(main_frame, bg="#ffffff")
+        options_frame.pack(pady=10)
+        
+        for i, option in enumerate(options):
+            tk.Radiobutton(options_frame, text=f"{['A', 'B', 'C', 'D'][i]}. {option}", 
+                          variable=self.answer_var, value=str(option), font=self.normal_font,
+                          bg="#ffffff", selectcolor="#e0e0e0", activebackground="#f0f0f0").pack(anchor="w", padx=50, pady=5)
+        
+        # 按钮框架
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=20)
+        
+        if self.current_quiz.current_question_index > 0:
+            tk.Button(button_frame, text="上一题", command=self.previous_question, bg="#cccccc", fg=self.dark_text,
+                     font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(side="left", padx=10)
+        
+        tk.Button(button_frame, text="提交答案", command=self.submit_answer, bg=self.success_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(side="left", padx=10)
+        
+        if self.current_quiz.current_question_index < len(self.current_quiz.questions) - 1:
+            tk.Button(button_frame, text="下一题", command=self.next_question, bg=self.primary_color, fg="white",
+                     font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(side="left", padx=10)
+        
+        tk.Button(main_frame, text="返回主菜单", command=self.show_main_menu_frame, width=15, bg=self.danger_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=10)
+        
+        self.show_frame(self.quiz_frame)
+
+    def generate_options(self, correct_answer) -> List[float]:
+        """
+        为题目生成选项
+        
+        @param correct_answer: 正确答案
+        @return: 选项列表
+        """
+        # 生成4个选项，其中一个是正确答案
+        options = {correct_answer}
+        
+        # 添加一些干扰项
+        if isinstance(correct_answer, int):
+            while len(options) < 4:
+                offset = random.randint(-10, 10)
+                if offset != 0:
+                    options.add(correct_answer + offset)
+        else:
+            # 浮点数情况
+            while len(options) < 4:
+                offset = random.uniform(-10, 10)
+                if abs(offset) > 0.1:  # 避免太接近正确答案
+                    options.add(round(correct_answer + offset, 2))
+        
+        # 如果选项不足4个，补充一些随机数
+        while len(options) < 4:
+            options.add(round(random.uniform(correct_answer - 20, correct_answer + 20), 2))
+        
+        options_list = list(options)
+        random.shuffle(options_list)
+        return options_list[:4]
+
+    def submit_answer(self):
+        """
+        提交答案
+        """
+        if not self.current_quiz:
+            return
+        
+        answer_str = self.answer_var.get()
+        if not answer_str:
+            messagebox.showerror("错误", "请选择一个答案")
+            return
+        
+        try:
+            answer = float(answer_str)
+            self.current_quiz.answer_question(answer)
+            
+            # 如果是最后一题，显示结果
+            if self.current_quiz.is_finished():
+                self.show_result_frame()
+            else:
+                messagebox.showinfo("提示", "答案已提交")
+        except ValueError:
+            messagebox.showerror("错误", "请选择有效答案")
+
+    def next_question(self):
+        """
+        下一题
+        """
+        if not self.current_quiz:
+            return
+        
+        # 保存当前答案（如果有选择）
+        answer_str = self.answer_var.get()
+        if answer_str:
+            try:
+                answer = float(answer_str)
+                self.current_quiz.answer_question(answer)
+            except ValueError:
+                pass  # 如果答案无效，保持为None
+        
+        if self.current_quiz.next_question():
+            self.show_quiz_frame()
+        else:
+            # 已经是最后一题
+            if self.current_quiz.answers[self.current_quiz.current_question_index] is not None:
+                # 如果最后一题已答题，显示结果
+                self.show_result_frame()
+            else:
+                messagebox.showinfo("提示", "已经是最后一题")
+
+    def previous_question(self):
+        """
+        上一题
+        """
+        if not self.current_quiz:
+            return
+        
+        # 保存当前答案（如果有选择）
+        answer_str = self.answer_var.get()
+        if answer_str:
+            try:
+                answer = float(answer_str)
+                self.current_quiz.answer_question(answer)
+            except ValueError:
+                pass  # 如果答案无效，保持为None
+        
+        if self.current_quiz.previous_question():
+            self.show_quiz_frame()
+
+    def show_result_frame(self):
+        """
+        显示结果界面
+        """
+        if not self.current_quiz:
+            return
+        
+        # 清除之前的内容
+        for widget in self.result_frame.winfo_children():
+            widget.destroy()
+        
+        # 计算得分
+        score = self.current_quiz.calculate_score()
+        
+        # 创建结果界面
+        main_frame = tk.Frame(self.result_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=30, padx=50, fill="both", expand=True)
+        
+        title_frame = tk.Frame(main_frame, bg=self.primary_color)
+        title_frame.pack(fill="x", pady=(0, 20))
+        tk.Label(title_frame, text="测验结果", font=self.title_font, bg=self.primary_color, fg="white").pack(pady=20)
+        
+        result_frame = tk.Frame(main_frame, bg="#ffffff")
+        result_frame.pack(pady=20)
+        
+        # 根据得分显示不同颜色的分数
+        score_color = self.danger_color if score < 60 else self.warning_color if score < 80 else self.success_color
+        
+        tk.Label(result_frame, text=f"您的得分: {score:.1f}%", font=("Arial", 20, "bold"), fg=score_color, bg="#ffffff").pack(pady=10)
+        
+        # 根据得分显示评语
+        if score >= 90:
+            comment = "优秀! 继续保持!"
+            comment_color = self.success_color
+        elif score >= 80:
+            comment = "良好! 还可以做得更好!"
+            comment_color = self.success_color
+        elif score >= 60:
+            comment = "及格了，需要继续努力!"
+            comment_color = self.warning_color
+        else:
+            comment = "需要加强练习哦!"
+            comment_color = self.danger_color
+        
+        tk.Label(result_frame, text=comment, font=self.header_font, fg=comment_color, bg="#ffffff").pack(pady=10)
+        
+        # 显示答题详情
+        correct_count = sum(1 for q, a in zip(self.current_quiz.questions, self.current_quiz.answers) 
+                           if a is not None and abs(q.answer - a) < 1e-6)
+        total_count = len(self.current_quiz.questions)
+        tk.Label(result_frame, text=f"答对: {correct_count}/{total_count}", font=self.normal_font, bg="#ffffff").pack(pady=5)
+        
+        # 按钮
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=30)
+        
+        level_names = {"elementary": "小学", "middle": "初中", "high": "高中"}
+        tk.Button(button_frame, text=f"继续{level_names[self.current_level]}题目", 
+                  command=lambda: self.show_quiz_setup_frame(self.current_level), width=20, bg=self.primary_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(side="left", padx=10)
+        
+        tk.Button(button_frame, text="返回主菜单", command=self.show_main_menu_frame, width=15, bg="#cccccc", fg=self.dark_text,
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(side="left", padx=10)
+        
+        self.show_frame(self.result_frame)
+
+    def show_change_password_frame(self):
+        """
+        显示修改密码界面
+        """
+        # 清除之前的内容
+        for widget in self.change_password_frame.winfo_children():
+            widget.destroy()
+        
+        # 创建修改密码界面
+        main_frame = tk.Frame(self.change_password_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=30, padx=50, fill="both", expand=True)
+        
+        title_frame = tk.Frame(main_frame, bg=self.primary_color)
+        title_frame.pack(fill="x", pady=(0, 20))
+        tk.Label(title_frame, text="修改密码", font=self.title_font, bg=self.primary_color, fg="white").pack(pady=20)
+        
+        form_frame = tk.Frame(main_frame, bg="#ffffff")
+        form_frame.pack(pady=10)
+        
+        tk.Label(form_frame, text="原密码:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.old_password_entry = tk.Entry(form_frame, width=30, font=self.normal_font, show="*", relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.old_password_entry.pack(pady=5)
+        
+        tk.Label(form_frame, text="新密码:", font=self.normal_font, bg="#ffffff", fg=self.primary_color).pack(pady=(10, 5), anchor="w")
+        tk.Label(form_frame, text="（6-10位，必须包含大小写字母和数字）", font=("Arial", 10), bg="#ffffff", fg="gray").pack(pady=5, anchor="w")
+        self.new_password_entry = tk.Entry(form_frame, width=30, font=self.normal_font, show="*", relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.new_password_entry.pack(pady=5)
+        
+        tk.Label(form_frame, text="确认新密码:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.confirm_new_password_entry = tk.Entry(form_frame, width=30, font=self.normal_font, show="*", relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.confirm_new_password_entry.pack(pady=5)
+        
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=20)
+        
+        tk.Button(button_frame, text="修改密码", command=self.change_password, width=20, bg=self.success_color, fg="white",
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=10)
+        tk.Button(button_frame, text="返回主菜单", command=self.show_main_menu_frame, width=20, bg="#cccccc", fg=self.dark_text,
+                 font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(pady=5)
+        
+        self.show_frame(self.change_password_frame)
+
+    def change_password(self):
+        """
+        修改密码
+        """
+        old_password = self.old_password_entry.get()
+        new_password = self.new_password_entry.get()
+        confirm_new_password = self.confirm_new_password_entry.get()
+        
+        if not old_password or not new_password or not confirm_new_password:
+            messagebox.showerror("错误", "请填写所有字段")
+            return
+        
+        if new_password != confirm_new_password:
+            messagebox.showerror("错误", "新密码和确认密码不一致")
+            return
+        
+        if self.user_manager.change_password(old_password, new_password):
+            messagebox.showinfo("成功", "密码修改成功")
+            self.show_main_menu_frame()
+        # 错误信息在user_manager.change_password中已经显示
+
+    def logout(self):
+        """
+        退出登录
+        """
+        self.user_manager.logout()
+        self.show_login_frame()
+
+    def show_delete_account_frame(self):
+        """
+        显示注销账户界面
+        """
+        # 清除之前的内容
+        for widget in self.delete_account_frame.winfo_children():
+            widget.destroy()
+        
+        # 创建注销账户界面
+        main_frame = tk.Frame(self.delete_account_frame, bg="#ffffff", relief=tk.RAISED, bd=2)
+        main_frame.pack(pady=30, padx=50, fill="both", expand=True)
+        
+        title_frame = tk.Frame(main_frame, bg=self.danger_color)
+        title_frame.pack(fill="x", pady=(0, 20))
+        tk.Label(title_frame, text="注销账户", font=self.title_font, bg=self.danger_color, fg="white").pack(pady=20)
+        
+        warning_frame = tk.Frame(main_frame, bg="#ffffff")
+        warning_frame.pack(pady=10)
+        
+        tk.Label(warning_frame, text="警告：此操作将永久删除您的账户和所有数据！", font=self.normal_font, fg=self.danger_color, bg="#ffffff").pack(pady=5)
+        tk.Label(warning_frame, text="请确认您的邮箱和密码：", font=self.normal_font, fg=self.danger_color, bg="#ffffff").pack(pady=5)
+        
+        form_frame = tk.Frame(main_frame, bg="#ffffff")
+        form_frame.pack(pady=10)
+        
+        tk.Label(form_frame, text="邮箱:", font=self.normal_font, bg="#ffffff").pack(pady=10, anchor="w")
+        self.delete_email_entry = tk.Entry(form_frame, width=30, font=self.normal_font, relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.delete_email_entry.pack(pady=5)
+        
+        tk.Label(form_frame, text="密码:", font=self.normal_font, bg="#ffffff").pack(pady=5, anchor="w")
+        self.delete_password_entry = tk.Entry(form_frame, width=30, font=self.normal_font, show="*", relief=tk.FLAT, bd=5, bg="#f0f0f0")
+        self.delete_password_entry.pack(pady=5)
+        
+        # 按钮框架
+        button_frame = tk.Frame(main_frame, bg="#ffffff")
+        button_frame.pack(pady=20)
+        
+        tk.Button(button_frame, text="确认注销", command=self.confirm_delete_account, 
+                  width=15, bg=self.danger_color, fg="white", font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(side="left", padx=10)
+        tk.Button(button_frame, text="取消", command=self.show_login_frame,
+                  width=15, bg="#cccccc", fg=self.dark_text, font=self.button_font, relief=tk.FLAT, bd=0, padx=10, pady=5).pack(side="left", padx=10)
+        
+        self.show_frame(self.delete_account_frame)
+
+    def confirm_delete_account(self):
+        """
+        确认并执行账户删除操作
+        """
+        email = self.delete_email_entry.get().strip()
+        password = self.delete_password_entry.get()
+        
+        if not email or not password:
+            messagebox.showerror("错误", "请输入邮箱和密码")
+            return
+        
+        # 确认操作
+        if messagebox.askyesno("确认注销", "确定要注销账户吗？此操作无法撤销！"):
+            if self.user_manager.delete_account(email, password):
+                messagebox.showinfo("成功", "账户已注销，您可以使用该邮箱重新注册")
+                self.show_login_frame()
+            # 错误信息在user_manager.delete_account中已经显示
+
+    def delete_account(self):
+        """
+        注销账户（从主菜单调用的旧方法，保持兼容性）
+        """
+        self.show_delete_account_frame()
\ No newline at end of file
diff --git a/src/question_bank.py b/src/question_bank.py
new file mode 100644
index 0000000..20925a9
--- /dev/null
+++ b/src/question_bank.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+"""
+题库模块
+"""
+
+from typing import List, Dict
+from question_generator import Expression, ElementaryQuestionGenerator, MiddleQuestionGenerator, HighQuestionGenerator
+
+
+class QuestionBank:
+    """
+    题库类，管理不同难度的题目生成器
+    """
+
+    def __init__(self):
+        """
+        初始化题库
+        """
+        self.generators = {
+            "elementary": ElementaryQuestionGenerator(),
+            "middle": MiddleQuestionGenerator(),
+            "high": HighQuestionGenerator()
+        }
+
+    def generate_questions(self, level: str, count: int) -> List[Expression]:
+        """
+        生成指定数量和难度的题目
+        
+        @param level: 题目难度（elementary, middle, high）
+        @param count: 题目数量
+        @return: 题目列表
+        """
+        if level not in self.generators:
+            raise ValueError("无效的题目难度")
+        
+        generator = self.generators[level]
+        questions = []
+        
+        for _ in range(count):
+            question = generator.generate_question()
+            questions.append(question)
+        
+        return questions
\ No newline at end of file
diff --git a/src/question_generator.py b/src/question_generator.py
new file mode 100644
index 0000000..ed473d3
--- /dev/null
+++ b/src/question_generator.py
@@ -0,0 +1,408 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+"""
+题目生成器模块
+"""
+
+import random
+import math
+import re
+from abc import ABC, abstractmethod
+from typing import List, Set, Optional
+
+
+class Expression:
+    """
+    数学表达式类
+    """
+
+    def __init__(self, expression_str: str, answer: float):
+        """
+        初始化表达式
+        
+        @param expression_str: 表达式字符串
+        @param answer: 表达式答案
+        """
+        self.expression_str = expression_str
+        self.answer = answer
+
+    def __str__(self) -> str:
+        """
+        返回表达式的字符串表示
+        
+        @return: 表达式字符串
+        """
+        return self.expression_str
+
+    def __eq__(self, other) -> bool:
+        """
+        比较两个表达式是否相等
+        
+        @param other: 另一个表达式
+        @return: 是否相等
+        """
+        if isinstance(other, Expression):
+            return self.expression_str == other.expression_str
+        return False
+
+    def __hash__(self) -> int:
+        """
+        计算表达式的哈希值
+        
+        @return: 哈希值
+        """
+        return hash(self.expression_str)
+
+
+class QuestionGenerator(ABC):
+    """
+    题目生成器抽象基类
+    """
+
+    def __init__(self):
+        """
+        初始化题目生成器
+        """
+        self.generated_questions: Set[str] = set()
+        self.load_existing_questions()
+
+    def load_existing_questions(self) -> None:
+        """
+        加载已存在的题目用于查重
+        """
+        # 在实际应用中，可以从文件或其他存储中加载已存在的题目
+        pass
+
+    @abstractmethod
+    def generate_question(self) -> Expression:
+        """
+        生成题目（抽象方法）
+        
+        @return: 数学表达式
+        """
+        pass
+
+
+class ElementaryQuestionGenerator(QuestionGenerator):
+    """
+    小学题目生成器（+, -, *, /, 括号）
+    """
+
+    def generate_question(self) -> Expression:
+        """
+        生成小学题目
+        
+        @return: 数学表达式
+        """
+        max_attempts = 100
+        for _ in range(max_attempts):
+            # 随机生成操作数数量（2-5个）
+            num_operands = random.randint(2, 5)
+            operands = [random.randint(1, 50) for _ in range(num_operands)]
+            operators = [random.choice(['+', '-', '*']) if random.random() < 0.8 else '/' 
+                        for _ in range(num_operands - 1)]  # 减少减法和除法概率以避免负数
+            
+            # 随机添加括号
+            expression_parts = []
+            for i in range(num_operands):
+                expression_parts.append(str(operands[i]))
+                if i < len(operators):
+                    expression_parts.append(operators[i])
+            
+            # 随机添加括号
+            if num_operands >= 3 and random.random() < 0.3:
+                # 在随机位置添加括号
+                open_pos = random.randint(0, len(expression_parts) - 3)
+                # 确保括号内至少有两个操作数
+                close_pos = min(open_pos + 2 + random.randint(1, 2) * 2, len(expression_parts))
+                
+                # 确保括号位置是操作数位置
+                if open_pos % 2 == 0 and close_pos % 2 == 0:
+                    expression_parts.insert(open_pos, '(')
+                    expression_parts.insert(close_pos + 1, ')')
+            
+            expression_str = ''.join(expression_parts)
+            
+            # 验证表达式是否有效
+            try:
+                # 替换除法符号以便计算
+                eval_expr = expression_str.replace('/', '/').replace('*', '*')
+                result = eval(eval_expr)
+                
+                # 确保结果是非负数且是合理的（整数或有限小数）
+                if isinstance(result, (int, float)) and result >= 0 and abs(result) < 1000:
+                    # 格式化结果，保留合适的小数位数
+                    if isinstance(result, float) and result.is_integer():
+                        result = int(result)
+                    
+                    expr = Expression(expression_str, result)
+                    # 检查是否已生成过相同题目
+                    if str(expr) not in self.generated_questions:
+                        self.generated_questions.add(str(expr))
+                        # 将表达式中的乘号和除号替换为更易读的形式
+                        readable_expr_str = expression_str.replace('*', '×').replace('/', '÷')
+                        readable_expr = Expression(readable_expr_str, result)
+                        return readable_expr
+            except:
+                continue
+        
+        # 如果无法生成有效题目，返回默认题目
+        expr = Expression("1+1", 2)
+        self.generated_questions.add(str(expr))
+        readable_expr = Expression("1+1", 2)
+        return readable_expr
+
+
+class MiddleQuestionGenerator(QuestionGenerator):
+    """
+    初中题目生成器（包含平方或开根号）
+    """
+
+    def generate_question(self) -> Expression:
+        """
+        生成初中题目
+        
+        @return: 数学表达式
+        """
+        max_attempts = 100
+        for _ in range(max_attempts):
+            expression_parts = []
+            
+            # 确保至少有一个平方或开根号
+            has_square_or_sqrt = True  # 确保至少有一个平方或开根号
+            
+            # 生成操作数数量（2-5个）
+            num_operands = random.randint(2, 5)
+            
+            # 标记是否已添加特殊操作
+            special_added = False
+            
+            for i in range(num_operands):
+                # 确保至少添加一个平方或开根号
+                if not special_added and i == num_operands - 1:
+                    # 如果还没添加特殊操作，强制在最后一个操作数添加
+                    choice = random.choice([0, 1])  # 提高开根号概率
+                    if choice == 0:
+                        # 添加平方
+                        base = random.randint(1, 12)
+                        expression_parts.append(f"{base}²")
+                    else:
+                        # 添加开根号
+                        square = random.randint(1, 12)
+                        value = square * square
+                        expression_parts.append(f"√{value}")
+                    special_added = True
+                else:
+                    rand_val = random.random()
+                    # 修改这里的概率，增加开根号和平方的出现频率
+                    if not special_added and rand_val < 0.6:  # 提高特殊操作概率从0.4到0.6
+                        # 添加特殊操作（平方或开根号）
+                        choice = random.choice([0, 1]) if random.random() < 0.6 else 1  # 提高开根号概率
+                        if choice == 0:
+                            # 添加平方
+                            base = random.randint(1, 12)
+                            expression_parts.append(f"{base}²")
+                        else:
+                            # 添加开根号
+                            square = random.randint(1, 12)
+                            value = square * square
+                            expression_parts.append(f"√{value}")
+                        special_added = True
+                    else:
+                        # 普通操作数
+                        expression_parts.append(str(random.randint(1, 50)))
+                
+                # 添加运算符（除了最后一个操作数）
+                if i < num_operands - 1:
+                    expression_parts.append(random.choice(['+', '-', '*', '/']))
+            
+            expression_str = ''.join(expression_parts)
+            
+            # 处理可能的语法问题
+            expression_str = self.fix_expression_syntax(expression_str)
+            
+            # 计算结果
+            try:
+                # 替换表达式中的函数以便计算
+                eval_expr = expression_str.replace('²', '**2').replace('√', 'math.sqrt')
+                result = eval(eval_expr)
+                
+                # 确保结果是合理的
+                if isinstance(result, (int, float)) and abs(result) < 1000 and not math.isnan(result):
+                    # 格式化结果
+                    if isinstance(result, float) and abs(result - round(result)) < 1e-10:
+                        result = int(round(result))
+                    
+                    expr = Expression(expression_str, result)
+                    # 检查是否已生成过相同题目
+                    if str(expr) not in self.generated_questions:
+                        self.generated_questions.add(str(expr))
+                        # 将表达式中的乘号和除号替换为更易读的形式
+                        readable_expr_str = expression_str.replace('*', '×').replace('/', '÷')
+                        readable_expr = Expression(readable_expr_str, result)
+                        return readable_expr
+            except:
+                continue
+        
+        # 如果无法生成有效题目，返回默认题目
+        expr = Expression("√4+2²", 6)
+        self.generated_questions.add(str(expr))
+        readable_expr = Expression("√4+2²", 6)
+        # 将表达式中的乘号和除号替换为更易读的形式
+        readable_expr_str = "√4+2²".replace('*', '×').replace('/', '÷')
+        readable_expr = Expression(readable_expr_str, 6)
+        return readable_expr
+    
+    def fix_expression_syntax(self, expression: str) -> str:
+        """
+        修复表达式语法问题
+        
+        @param expression: 原始表达式
+        @return: 修复后的表达式
+        """
+        # 确保函数调用之间有运算符
+        expression = re.sub(r'(\d)([√])', r'\1*\2', expression)
+        expression = re.sub(r'(²)([√])', r'\1*\2', expression)
+        expression = re.sub(r'(\))(\d)', r'\1*\2', expression)
+        expression = re.sub(r'(\d)(\()', r'\1*\2', expression)
+        # 修复根号表达式显示，确保根号符号正确显示
+        expression = re.sub(r'√(\d+)', r'√\1', expression)
+        return expression
+
+
+class HighQuestionGenerator(QuestionGenerator):
+    """
+    高中题目生成器（包含三角函数）
+    """
+
+    def generate_question(self) -> Expression:
+        """
+        生成高中题目
+        
+        @return: 数学表达式
+        """
+        max_attempts = 100
+        for _ in range(max_attempts):
+            expression_parts = []
+            
+            # 确保至少有一个三角函数
+            has_trig_function = random.random() < 0.8
+            
+            # 生成操作数数量（2-4个）
+            num_operands = random.randint(2, 4)
+            
+            for i in range(num_operands):
+                if has_trig_function and i == 0:
+                    # 第一个操作数有较高概率是三角函数
+                    if random.random() < 0.33:
+                        angle = random.choice([0, 30, 45, 60, 90])
+                        expression_parts.append(f"sin({angle}°)")
+                    elif random.random() < 0.5:
+                        angle = random.choice([0, 30, 45, 60, 90])
+                        expression_parts.append(f"cos({angle}°)")
+                    else:
+                        angle = random.choice([0, 30, 45, 60, 90])
+                        expression_parts.append(f"tan({angle}°)")
+                else:
+                    # 其他操作数
+                    rand_val = random.random()
+                    if rand_val < 0.1 and has_trig_function:
+                        # 添加三角函数
+                        angle = random.choice([0, 30, 45, 60, 90])
+                        expression_parts.append(f"sin({angle}°)")
+                    elif rand_val < 0.2 and has_trig_function:
+                        angle = random.choice([0, 30, 45, 60, 90])
+                        expression_parts.append(f"cos({angle}°)")
+                    elif rand_val < 0.3 and has_trig_function:
+                        angle = random.choice([0, 30, 45, 60, 90])
+                        expression_parts.append(f"tan({angle}°)")
+                    elif rand_val < 0.55:
+                        # 普通数字
+                        expression_parts.append(str(random.randint(1, 20)))
+                    elif rand_val < 0.7:
+                        # 平方
+                        base = random.randint(1, 10)
+                        expression_parts.append(f"{base}²")
+                    else:
+                        # 开根号
+                        square = random.randint(1, 10)
+                        value = square * square
+                        expression_parts.append(f"√{value}")
+                
+                # 添加运算符（除了最后一个操作数）
+                if i < num_operands - 1:
+                    expression_parts.append(random.choice(['+', '-', '*', '/']))
+            
+            expression_str = ''.join(expression_parts)
+            
+            # 处理可能的语法问题
+            expression_str = self.fix_expression_syntax(expression_str)
+            
+            # 计算结果
+            try:
+                # 替换表达式中的函数以便计算
+                eval_expr = expression_str.replace('²', '**2').replace('√', 'math.sqrt')
+                # 修复：确保正确的替换顺序，先替换角度制三角函数
+                eval_expr = re.sub(r'sin\((\d+)°\)', r'math.sin(math.radians(\1))', eval_expr)
+                eval_expr = re.sub(r'cos\((\d+)°\)', r'math.cos(math.radians(\1))', eval_expr)
+                eval_expr = re.sub(r'tan\((\d+)°\)', r'math.tan(math.radians(\1))', eval_expr)
+                
+                result = eval(eval_expr)
+                
+                # 确保结果是合理的
+                if isinstance(result, (int, float)) and abs(result) < 1000 and not math.isnan(result) and not math.isinf(result):
+                    # 格式化结果
+                    if isinstance(result, float) and abs(result - round(result, 10)) < 1e-10:
+                        result = int(round(result))
+                    # 特殊处理常见的三角函数值，使其更加准确
+                    elif isinstance(result, float):
+                        # 对于常见的三角函数值进行舍入处理
+                        if abs(result - 0.5) < 1e-10:  # sin(30°) = 0.5
+                            result = 0.5
+                        elif abs(result - 0.7071067811865476) < 1e-10:  # sin(45°) = cos(45°) ≈ 0.707
+                            result = round(result, 10)
+                        elif abs(result - 0.8660254037844386) < 1e-10:  # sin(60°) ≈ 0.866
+                            result = round(result, 10)
+                        elif abs(result - 0.5773502691896257) < 1e-10:  # tan(30°) ≈ 0.577
+                            result = round(result, 10)
+                        elif abs(result - 1.7320508075688772) < 1e-10:  # tan(60°) ≈ 1.732
+                            result = round(result, 10)
+                        elif abs(result - 1.0) < 1e-10:  # tan(45°) = 1, sin(90°) = 1
+                            result = 1.0
+                    
+                    expr = Expression(expression_str, result)
+                    # 检查是否已生成过相同题目
+                    if str(expr) not in self.generated_questions:
+                        self.generated_questions.add(str(expr))
+                        # 将表达式中的乘号和除号替换为更易读的形式
+                        readable_expr_str = expression_str.replace('*', '×').replace('/', '÷')
+                        readable_expr = Expression(readable_expr_str, result)
+                        return readable_expr
+            except:
+                continue
+        
+        # 如果无法生成有效题目，返回默认题目
+        expr = Expression("sin(30°)", 0.5)
+        self.generated_questions.add(str(expr))
+        readable_expr = Expression("sin(30°)", 0.5)
+        # 将表达式中的乘号和除号替换为更易读的形式
+        readable_expr_str = "sin(30°)".replace('*', '×').replace('/', '÷')
+        readable_expr = Expression(readable_expr_str, 0.5)
+        return readable_expr
+    
+    def fix_expression_syntax(self, expression: str) -> str:
+        """
+        修复表达式语法问题
+        
+        @param expression: 原始表达式
+        @return: 修复后的表达式
+        """
+        # 确保函数调用之间有运算符
+        expression = re.sub(r'(\d)([sincostan√])', r'\1*\2', expression)
+        expression = re.sub(r'(²)([sincostan√])', r'\1*\2', expression)
+        expression = re.sub(r'(sqrt\(\d+\))(\d)', r'\1*\2', expression)
+        expression = re.sub(r'(\))(\d)', r'\1*\2', expression)
+        expression = re.sub(r'(\d)(\()', r'\1*\2', expression)
+        expression = re.sub(r'°\)(\d)', r'°)*\1', expression)
+        return expression
\ No newline at end of file
diff --git a/src/quiz.py b/src/quiz.py
new file mode 100644
index 0000000..80ae9a1
--- /dev/null
+++ b/src/quiz.py
@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+"""
+测验模块
+"""
+
+from typing import List, Optional
+from question_generator import Expression
+
+
+class Quiz:
+    """
+    测验类，管理一次答题过程
+    """
+
+    def __init__(self, questions: List[Expression]):
+        """
+        初始化测验
+        
+        @param questions: 题目列表
+        """
+        self.questions = questions
+        self.answers: List[Optional[float]] = [None] * len(questions)
+        self.current_question_index = 0
+        self.score = 0
+
+    def answer_question(self, answer: float) -> None:
+        """
+        回答当前题目
+        
+        @param answer: 用户答案
+        """
+        if 0 <= self.current_question_index < len(self.questions):
+            self.answers[self.current_question_index] = answer
+
+    def next_question(self) -> bool:
+        """
+        跳转到下一题
+        
+        @return: 是否有下一题
+        """
+        if self.current_question_index < len(self.questions) - 1:
+            self.current_question_index += 1
+            return True
+        return False
+
+    def previous_question(self) -> bool:
+        """
+        返回上一题
+        
+        @return: 是否有上一题
+        """
+        if self.current_question_index > 0:
+            self.current_question_index -= 1
+            return True
+        return False
+
+    def get_current_question(self) -> Optional[Expression]:
+        """
+        获取当前题目
+        
+        @return: 当前题目
+        """
+        if 0 <= self.current_question_index < len(self.questions):
+            return self.questions[self.current_question_index]
+        return None
+
+    def calculate_score(self) -> float:
+        """
+        计算得分
+        
+        @return: 得分（百分比）
+        """
+        correct_count = 0
+        for i, (question, answer) in enumerate(zip(self.questions, self.answers)):
+            if answer is not None:
+                # 允许一定的浮点数误差
+                if abs(question.answer - answer) < 1e-6:
+                    correct_count += 1
+        
+        self.score = (correct_count / len(self.questions)) * 100 if self.questions else 0
+        return self.score
+
+    def is_finished(self) -> bool:
+        """
+        检查测验是否已完成
+        
+        @return: 是否已完成
+        """
+        return self.current_question_index == len(self.questions) - 1 and self.answers[self.current_question_index] is not None
\ No newline at end of file
diff --git a/src/user_manager.py b/src/user_manager.py
new file mode 100644
index 0000000..a214d7e
--- /dev/null
+++ b/src/user_manager.py
@@ -0,0 +1,381 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+"""
+用户管理模块
+"""
+
+import json
+import os
+import re
+import random
+import hashlib
+import smtplib
+from email.mime.text import MIMEText
+from email.mime.multipart import MIMEMultipart
+from typing import Dict, Optional
+from tkinter import messagebox
+
+
+class User:
+    """
+    用户类，存储用户信息
+    """
+
+    def __init__(self, email: str, username: str = "", password_hash: str = "", registration_code: str = ""):
+        """
+        初始化用户对象
+        
+        @param email: 用户邮箱
+        @param username: 用户名
+        @param password_hash: 密码哈希值
+        @param registration_code: 注册码
+        """
+        self.email = email
+        self.username = username
+        self.password_hash = password_hash
+        self.registration_code = registration_code
+        self.is_registered = bool(password_hash)
+
+
+class UserManager:
+    """
+    用户管理类，负责处理用户注册、登录和密码管理
+    """
+
+    def __init__(self, data_file: str = "users.json"):
+        """
+        初始化用户管理器
+        
+        @param data_file: 存储用户数据的文件路径
+        """
+        self.data_file = data_file
+        self.users: Dict[str, User] = {}
+        self.current_user: Optional[User] = None
+        # 邮件配置
+        self.smtp_server = "smtp.qq.com"  # 可根据需要修改SMTP服务器
+        self.smtp_port = 465
+        self.sender_email = "3257534544@qq.com"  # 需要替换为实际邮箱
+        self.sender_password = "pmfyurbkwfpkdbed"  # 需要替换为实际应用密码
+        self.load_users()
+
+    def load_users(self) -> None:
+        """
+        从文件加载用户数据
+        """
+        if os.path.exists(self.data_file):
+            try:
+                with open(self.data_file, 'r', encoding='utf-8') as f:
+                    data = json.load(f)
+                    for email, user_data in data.items():
+                        user = User(
+                            email=email,
+                            username=user_data.get('username', ''),
+                            password_hash=user_data.get('password_hash', ''),
+                            registration_code=user_data.get('registration_code', '')
+                        )
+                        user.is_registered = user_data.get('is_registered', False)
+                        self.users[email] = user
+            except (json.JSONDecodeError, FileNotFoundError):
+                self.users = {}
+
+    def save_users(self) -> None:
+        """
+        保存用户数据到文件
+        """
+        data = {}
+        for email, user in self.users.items():
+            data[email] = {
+                'username': user.username,
+                'password_hash': user.password_hash,
+                'registration_code': user.registration_code,
+                'is_registered': user.is_registered
+            }
+        
+        try:
+            with open(self.data_file, 'w', encoding='utf-8') as f:
+                json.dump(data, f, ensure_ascii=False, indent=2)
+        except IOError as e:
+            messagebox.showerror("错误", f"保存用户数据失败: {str(e)}")
+
+    def is_valid_email(self, email: str) -> bool:
+        """
+        验证邮箱格式
+        
+        @param email: 邮箱地址
+        @return: 邮箱格式是否有效
+        """
+        pattern = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'
+        return re.match(pattern, email) is not None
+
+    def is_valid_username(self, username: str) -> bool:
+        """
+        验证用户名是否符合要求
+        
+        @param username: 用户名
+        @return: 用户名是否有效
+        """
+        # 用户名长度应在3-20个字符之间
+        if not (3 <= len(username) <= 20):
+            return False
+        # 用户名只能包含字母、数字和下划线
+        pattern = r'^[a-zA-Z0-9_]+$'
+        return re.match(pattern, username) is not None
+
+    def generate_registration_code(self) -> str:
+        """
+        生成注册码
+        
+        @return: 6位数字注册码
+        """
+        return str(random.randint(100000, 999999))
+
+    def hash_password(self, password: str) -> str:
+        """
+        对密码进行哈希处理
+        
+        @param password: 原始密码
+        @return: 哈希后的密码
+        """
+        return hashlib.sha256(password.encode('utf-8')).hexdigest()
+
+    def is_valid_password(self, password: str) -> bool:
+        """
+        验证密码是否符合要求
+        
+        @param password: 密码
+        @return: 密码是否有效
+        """
+        if not (6 <= len(password) <= 10):
+            return False
+        
+        has_lower = any(c.islower() for c in password)
+        has_upper = any(c.isupper() for c in password)
+        has_digit = any(c.isdigit() for c in password)
+        
+        return has_lower and has_upper and has_digit
+
+    def register_user(self, email: str, username: str) -> bool:
+        """
+        注册新用户（发送注册码）
+        
+        @param email: 用户邮箱
+        @param username: 用户名
+        @return: 是否成功发送注册码
+        """
+        if not self.is_valid_email(email):
+            messagebox.showerror("错误", "邮箱格式不正确")
+            return False
+            
+        if not self.is_valid_username(username):
+            messagebox.showerror("错误", "用户名应为3-20位，只能包含字母、数字和下划线")
+            return False
+        
+        # 检查邮箱是否已被注册
+        if email in self.users and self.users[email].is_registered:
+            messagebox.showerror("错误", "该邮箱已注册")
+            return False
+            
+        # 检查用户名是否已被使用
+        for user in self.users.values():
+            if user.username == username and user.is_registered:
+                messagebox.showerror("错误", "该用户名已存在")
+                return False
+        
+        registration_code = self.generate_registration_code()
+        user = User(email=email, username=username, registration_code=registration_code)
+        self.users[email] = user
+        
+        # 尝试发送邮件
+        if self.send_registration_code_via_email(email, registration_code):
+            self.save_users()
+            messagebox.showinfo("成功", "注册码已发送到您的邮箱，请查收")
+            return True
+        else:
+            messagebox.showerror("错误", "无法发送注册码到邮箱，请检查网络连接或邮箱地址")
+            # 即使邮件发送失败，也保存用户信息以便重试
+            self.save_users()
+            return False
+
+    def send_registration_code_via_email(self, email: str, code: str) -> bool:
+        """
+        通过电子邮件发送注册码
+        
+        @param email: 接收邮箱
+        @param code: 注册码
+        @return: 是否发送成功
+        """
+        try:
+            # 创建邮件内容
+            message = MIMEMultipart()
+            message["From"] = self.sender_email
+            message["To"] = email
+            message["Subject"] = "数学练习系统注册码"
+            
+            body = f"""
+            您好！
+            
+            欢迎使用数学练习系统！
+            
+            您的注册码是: {code}
+            
+            请在注册界面输入此注册码完成注册。
+            
+            如果您没有请求此注册码，请忽略此邮件。
+            
+            祝学习愉快！
+            数学练习系统团队
+            """
+            
+            message.attach(MIMEText(body, "plain", "utf-8"))
+            
+            # 使用SMTP_SSL连接QQ邮箱服务器
+            server = smtplib.SMTP_SSL(self.smtp_server, self.smtp_port)
+            server.login(self.sender_email, self.sender_password)
+            text = message.as_string()
+            server.sendmail(self.sender_email, email, text)
+            server.quit()
+            
+            return True
+        except Exception as e:
+            print(f"邮件发送失败: {str(e)}")
+            return False
+
+    def verify_registration_code(self, email: str, code: str) -> bool:
+        """
+        验证注册码
+        
+        @param email: 用户邮箱
+        @param code: 用户输入的注册码
+        @return: 注册码是否正确
+        """
+        if email not in self.users:
+            messagebox.showerror("错误", "请先获取注册码")
+            return False
+        
+        user = self.users[email]
+        if user.registration_code != code:
+            messagebox.showerror("错误", "注册码不正确")
+            return False
+        
+        return True
+
+    def set_password(self, email: str, password: str) -> bool:
+        """
+        设置用户密码
+        
+        @param email: 用户邮箱
+        @param password: 用户密码
+        @return: 是否设置成功
+        """
+        if not self.is_valid_password(password):
+            messagebox.showerror("错误", "密码必须为6-10位，且包含大小写字母和数字")
+            return False
+        
+        if email not in self.users:
+            messagebox.showerror("错误", "用户不存在")
+            return False
+        
+        user = self.users[email]
+        user.password_hash = self.hash_password(password)
+        user.is_registered = True
+        self.save_users()
+        return True
+
+    def login(self, username: str, password: str) -> bool:
+        """
+        用户登录
+        
+        @param username: 用户名
+        @param password: 用户密码
+        @return: 是否登录成功
+        """
+        # 根据用户名查找用户
+        user = None
+        for u in self.users.values():
+            if u.username == username:
+                user = u
+                break
+                
+        if user is None:
+            messagebox.showerror("错误", "用户不存在")
+            return False
+        
+        if not user.is_registered:
+            messagebox.showerror("错误", "请先完成注册")
+            return False
+        
+        if user.password_hash != self.hash_password(password):
+            messagebox.showerror("错误", "密码不正确")
+            return False
+        
+        self.current_user = user
+        return True
+
+    def change_password(self, old_password: str, new_password: str) -> bool:
+        """
+        修改用户密码
+        
+        @param old_password: 原密码
+        @param new_password: 新密码
+        @return: 是否修改成功
+        """
+        if not self.current_user:
+            messagebox.showerror("错误", "用户未登录")
+            return False
+        
+        if self.current_user.password_hash != self.hash_password(old_password):
+            messagebox.showerror("错误", "原密码不正确")
+            return False
+        
+        if not self.is_valid_password(new_password):
+            messagebox.showerror("错误", "新密码必须为6-10位，且包含大小写字母和数字")
+            return False
+        
+        self.current_user.password_hash = self.hash_password(new_password)
+        self.save_users()
+        return True
+
+    def logout(self) -> None:
+        """
+        用户登出
+        """
+        self.current_user = None
+    
+    def delete_account(self, email: str, password: str) -> bool:
+        """
+        注销账户
+        
+        @param email: 用户邮箱
+        @param password: 用户密码
+        @return: 是否注销成功
+        """
+        if not self.is_valid_email(email):
+            messagebox.showerror("错误", "邮箱格式不正确")
+            return False
+        
+        # 检查用户是否存在
+        if email not in self.users:
+            messagebox.showerror("错误", "该邮箱未注册")
+            return False
+        
+        user = self.users[email]
+        
+        # 检查用户是否已完成注册
+        if not user.is_registered:
+            messagebox.showerror("错误", "该账户未完成注册")
+            return False
+        
+        # 验证密码
+        if user.password_hash != self.hash_password(password):
+            messagebox.showerror("错误", "密码不正确")
+            return False
+        
+        # 删除用户
+        del self.users[email]
+        # 如果当前用户是被删除的用户，则登出
+        if self.current_user and self.current_user.email == email:
+            self.current_user = None
+            
+        self.save_users()
+        return True
diff --git a/src/users.json b/src/users.json
new file mode 100644
index 0000000..0e0979a
--- /dev/null
+++ b/src/users.json
@@ -0,0 +1,8 @@
+{
+  "1426688201@qq.com": {
+    "username": "111",
+    "password_hash": "c4318372f98f4c46ed3a32c16ee4d7a76c832886d887631c0294b3314f34edf1",
+    "registration_code": "939598",
+    "is_registered": true
+  }
+}
\ No newline at end of file