diff --git a/middlewares.py b/middlewares.py
index 7f89cd1..2e2b1ba 100644
--- a/middlewares.py
+++ b/middlewares.py
@@ -63,7 +63,7 @@ def write2csv(category, response):    # 写入csv文件
     filename_csv = os.getcwd() + "\\Catalogues\\" + FILENAME_CSV.get(category)
     pipelines.write2csv(response, filename_csv)
 
-class milkSpider:
+class milkSpider:   # 定义一个爬虫类
     def __init__(self, url):
         self.url = url
         self.category = getCategory(url)
@@ -73,7 +73,7 @@ class milkSpider:
         print("write2csv for '{}' was started.".format(self.url))
         write2csv(self.category, self.response)
 
-def mainThread():
+def mainThread():   # 主线程，配置线程池状况，实例化爬虫对象
     try:
         with ThreadPoolExecutor(max_workers = 8) as thread:
             while True: