diff --git a/lib/main.dart b/lib/main.dart
index 99109ef..28ea652 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -1,5 +1,5 @@
 import 'package:flutter/material.dart';
-import 'package:timemanage/screens/dashboard_screen.dart';
+import 'package:timemanage/screen/dashboard_screen.dart';
 
 void main() => runApp(const MyApp());
 
diff --git a/lib/model/clone_time.dart b/lib/model/clone_time.dart
new file mode 100644
index 0000000..6d46c50
--- /dev/null
+++ b/lib/model/clone_time.dart
@@ -0,0 +1,7 @@
+// 拓展DateTime，实现克隆方法
+extension CloneTime on DateTime {
+  DateTime clone() {
+    return DateTime(
+        year, month, day, hour, minute, second, millisecond, microsecond);
+  }
+}
diff --git a/lib/model/project.dart b/lib/model/project.dart
new file mode 100644
index 0000000..b18fd4e
--- /dev/null
+++ b/lib/model/project.dart
@@ -0,0 +1,29 @@
+import 'package:flutter/material.dart'; // Color类要使用这个包
+import 'package:equatable/equatable.dart'; // 比较两个对象是否相等的包
+
+class Project extends Equatable {
+  final int id;
+  final String name;
+  final bool archived; // 是否归档
+
+  // 构造函数
+  const Project({
+    required this.id,
+    required this.name,
+    required this.archived,
+  });
+
+  @override
+  List<Object> get props => [id, name, archived]; // 返回属性列表，用于比较两个对象是否相等
+
+  Project.clone(
+    Project project, {
+    String? name,
+    Color? color,
+    bool? archived,
+  }) : this(
+          id: project.id,
+          name: name ?? project.name,
+          archived: archived ?? project.archived,
+        );
+}
diff --git a/lib/model/project_description.dart b/lib/model/project_description.dart
new file mode 100644
index 0000000..dcc66dd
--- /dev/null
+++ b/lib/model/project_description.dart
@@ -0,0 +1,12 @@
+import 'package:equatable/equatable.dart';
+
+// 项目描述
+class ProjectDescriptionPair extends Equatable {
+  final int? project;
+  final String? description;
+
+  const ProjectDescriptionPair(this.project, this.description);
+
+  @override
+  List<Object?> get props => [project, description];
+}
diff --git a/lib/model/start_of_week.dart b/lib/model/start_of_week.dart
new file mode 100644
index 0000000..3606d47
--- /dev/null
+++ b/lib/model/start_of_week.dart
@@ -0,0 +1,8 @@
+// 设置每周的第一天从周日开始
+extension StartOfWeek on DateTime {
+  DateTime startOfWeek({int startOfWeekDay = DateTime.sunday}) {
+    int diff = (7 + (weekday - startOfWeekDay)) % 7;
+    DateTime dt = add(Duration(days: -diff));
+    return DateTime(dt.year, dt.month, dt.day);
+  }
+}
diff --git a/lib/model/theme_type.dart b/lib/model/theme_type.dart
new file mode 100644
index 0000000..486699d
--- /dev/null
+++ b/lib/model/theme_type.dart
@@ -0,0 +1 @@
+// TODO: 实现主题切换功能
diff --git a/lib/model/timer_entry.dart b/lib/model/timer_entry.dart
new file mode 100644
index 0000000..e842a75
--- /dev/null
+++ b/lib/model/timer_entry.dart
@@ -0,0 +1,58 @@
+import 'package:equatable/equatable.dart';
+
+// 计时器实体类
+class TimerEntry extends Equatable {
+  final int id;
+  final String? description;
+  final int? projectID;
+  final DateTime startTime;
+  final DateTime? endTime;
+  final String? notes;
+
+  // 构造函数
+  const TimerEntry(
+      {required this.id,
+      required this.description,
+      required this.projectID,
+      required this.startTime,
+      required this.endTime,
+      this.notes = ""});
+
+  // 返回属性列表，用于比较两个对象是否相等
+  @override
+  List<Object?> get props =>
+      [id, description, projectID, startTime, endTime, notes];
+  @override
+  bool get stringify => true;
+
+  // 克隆方法
+  TimerEntry.clone(TimerEntry timer,
+      {String? description,
+      int? projectID,
+      DateTime? startTime,
+      DateTime? endTime,
+      String? notes})
+      : this(
+          id: timer.id,
+          description: description ?? timer.description,
+          projectID: projectID ?? timer.projectID,
+          startTime: startTime ?? timer.startTime,
+          endTime: endTime ?? timer.endTime,
+          notes: notes ?? timer.notes,
+        );
+
+  // 格式化时间
+  static String formatDuration(Duration d) {
+    if (d.inHours > 0) {
+      return "${d.inHours}:${(d.inMinutes - (d.inHours * 60)).toString().padLeft(2, "0")}:${(d.inSeconds - (d.inMinutes * 60)).toString().padLeft(2, "0")}";
+    } else {
+      return "${d.inMinutes.toString().padLeft(2, "0")}:${(d.inSeconds - (d.inMinutes * 60)).toString().padLeft(2, "0")}";
+    }
+  }
+
+  // 格式化时间
+  String formatTime() {
+    Duration d = (endTime ?? DateTime.now()).difference(startTime);
+    return formatDuration(d);
+  }
+}
diff --git a/lib/screens/about_screen.dart b/lib/screen/about_screen.dart
similarity index 98%
rename from lib/screens/about_screen.dart
rename to lib/screen/about_screen.dart
index 490a78f..e68dff8 100644
--- a/lib/screens/about_screen.dart
+++ b/lib/screen/about_screen.dart
@@ -68,7 +68,6 @@ class AboutScreen extends StatelessWidget {
                     ScaffoldMessenger.of(context).showSnackBar(
                       const SnackBar(
                           content: Text("请横屏查看"),
-                          // FIXME: 此处持续时间没有3秒
                           duration: Duration(seconds: 3)),
                     );
                     launchUrl(Uri.parse(
diff --git a/lib/screens/course_screen.dart b/lib/screen/course_screen.dart
similarity index 100%
rename from lib/screens/course_screen.dart
rename to lib/screen/course_screen.dart
diff --git a/lib/screens/dashboard_screen.dart b/lib/screen/dashboard_screen.dart
similarity index 85%
rename from lib/screens/dashboard_screen.dart
rename to lib/screen/dashboard_screen.dart
index bdf286e..713a934 100644
--- a/lib/screens/dashboard_screen.dart
+++ b/lib/screen/dashboard_screen.dart
@@ -1,10 +1,10 @@
 import 'package:flutter/material.dart';
-import 'package:timemanage/screens/projects_screen.dart';
-import 'package:timemanage/screens/reports_screen.dart';
-import 'package:timemanage/screens/export_screen.dart';
-import 'package:timemanage/screens/settings_screen.dart';
-import 'package:timemanage/screens/about_screen.dart';
-import 'package:timemanage/screens/course_screen.dart';
+import 'package:timemanage/screen/projects_screen.dart';
+import 'package:timemanage/screen/reports_screen.dart';
+import 'package:timemanage/screen/export_screen.dart';
+import 'package:timemanage/screen/settings_screen.dart';
+import 'package:timemanage/screen/about_screen.dart';
+import 'package:timemanage/screen/course_screen.dart';
 
 class DashBoardScreen extends StatelessWidget {
   const DashBoardScreen({super.key});
@@ -100,7 +100,14 @@ class DashBoardScreen extends StatelessWidget {
         ],
       ),
       body: const Center(
-        child: Text('主界面'),
+        child: Column(
+          children: [
+            Text('项目列表区'),
+            Expanded(
+              child: Text('计时器区'),
+            ),
+          ],
+        ),
       ),
     );
   }
diff --git a/lib/screens/export_screen.dart b/lib/screen/export_screen.dart
similarity index 100%
rename from lib/screens/export_screen.dart
rename to lib/screen/export_screen.dart
diff --git a/lib/screens/projects_screen.dart b/lib/screen/projects_screen.dart
similarity index 100%
rename from lib/screens/projects_screen.dart
rename to lib/screen/projects_screen.dart
diff --git a/lib/screens/reports_screen.dart b/lib/screen/reports_screen.dart
similarity index 100%
rename from lib/screens/reports_screen.dart
rename to lib/screen/reports_screen.dart
diff --git a/lib/screens/settings_screen.dart b/lib/screen/settings_screen.dart
similarity index 100%
rename from lib/screens/settings_screen.dart
rename to lib/screen/settings_screen.dart
diff --git a/pubspec.lock b/pubspec.lock
index ceba0e3..7207144 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -89,6 +89,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.6"
+  equatable:
+    dependency: "direct main"
+    description:
+      name: equatable
+      sha256: c2b87cb7756efdf69892005af546c56c0b5037f54d2a88269b4f347a505e3ca2
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.5"
   fake_async:
     dependency: transitive
     description:
diff --git a/pubspec.yaml b/pubspec.yaml
index bbb7ad9..668033e 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -36,7 +36,7 @@ dependencies:
   about: ^2.1.3
   font_awesome_flutter: ^9.2.0
   url_launcher: ^6.1.14
-
+  equatable: ^2.0.3 # 用于对象比较
 
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.