diff --git a/app/Article.py b/app/Article.py
index d5e63cd..df9ac3a 100644
--- a/app/Article.py
+++ b/app/Article.py
@@ -22,12 +22,12 @@ def total_number_of_essays():
     return len(result)
 
 
-def get_article_title(article):
-    return article.split('\n')[0]
+def get_article_title(s):
+    return s.split('\n')[0]
 
 
-def get_article_body(article):
-    lst = article.split('\n')
+def get_article_body(s):
+    lst = s.split('\n')
     lst.pop(0)  # remove the first line
     return '\n'.join(lst)
 
@@ -111,11 +111,11 @@ def within_range(x, y, r):
     return x > y and abs(x - y) <= r
 
 
-def get_question_part(article):
-    article = article.strip()
+def get_question_part(s):
+    s = s.strip()
     result = []
     flag = 0
-    for line in article.split('\n'):
+    for line in s.split('\n'):
         line = line.strip()
         if line == 'QUESTION':
             result.append(line)
@@ -127,11 +127,11 @@ def get_question_part(article):
     return '\n'.join(result)
 
 
-def get_answer_part(article):
-    article = article.strip()
+def get_answer_part(s):
+    s = s.strip()
     result = []
     flag = 0
-    for line in article.split('\n'):
+    for line in s.split('\n'):
         line = line.strip()
         if line == 'ANSWER':
             flag = 1
diff --git a/app/Login.py b/app/Login.py
index 2e2cecd..cd750d1 100644
--- a/app/Login.py
+++ b/app/Login.py
@@ -3,7 +3,6 @@ import string
 from datetime import datetime, timedelta
 from UseSqlite import InsertQuery, RecordQuery
 
-
 def md5(s):
     '''
     MD5摘要
@@ -13,16 +12,14 @@ def md5(s):
     h = hashlib.md5(s.encode(encoding='utf-8'))
     return h.hexdigest()
 
-
 # import model.user after the defination of md5(s) to avoid circular import
 from model.user import get_user_by_username, insert_user, update_password_by_username
 
 path_prefix = '/var/www/wordfreq/wordfreq/'
 path_prefix = './'  # comment this line in deployment
 
-
-def verify_pass(new_password, old_password):
-    if new_password == old_password:
+def verify_pass(newpass,oldpass):
+    if(newpass==oldpass):
         return True
 
 
@@ -56,7 +53,7 @@ def change_password(username, old_password, new_password):
     if not verify_user(username, old_password):  # 旧密码错误
         return False
     # 将用户名和密码一起加密，以免暴露不同用户的相同密码
-    if verify_pass(new_password, old_password):  #新旧密码一致
+    if verify_pass(new_password,old_password): #新旧密码一致
         return False
     update_password_by_username(username, new_password)
     return True
@@ -76,11 +73,11 @@ class UserName:
     def validate(self):
         if len(self.username) > 20:
             return f'{self.username} is too long.  The user name cannot exceed 20 characters.'
-        if self.username.startswith('.'):  # a user name must not start with a dot
+        if self.username.startswith('.'): # a user name must not start with a dot
             return 'Period (.) is not allowed as the first letter in the user name.'
-        if ' ' in self.username:  # a user name must not include a whitespace
+        if ' ' in self.username: # a user name must not include a whitespace
             return 'Whitespace is not allowed in the user name.'
-        for c in self.username:  # a user name must not include special characters, except non-leading periods or underscores
+        for c in self.username: # a user name must not include special characters, except non-leading periods or underscores
             if c in string.punctuation and c != '.' and c != '_':
                 return f'{c} is not allowed in the user name.'
         if self.username in ['signup', 'login', 'logout', 'reset', 'mark', 'back', 'unfamiliar', 'familiar', 'del', 'admin']:
diff --git a/app/account_service.py b/app/account_service.py
index 7259e15..a7ed0c4 100644
--- a/app/account_service.py
+++ b/app/account_service.py
@@ -43,6 +43,7 @@ def signup():
                 return jsonify({'status': '1'})
 
 
+
 @accountService.route("/login", methods=['GET', 'POST'])
 def login():
     '''
diff --git a/app/difficulty.py b/app/difficulty.py
index 03d3bfa..cb93768 100644
--- a/app/difficulty.py
+++ b/app/difficulty.py
@@ -18,25 +18,25 @@ def load_record(pickle_fname):
     return d
 
 
-def convert_test_type_to_difficulty_level(words_dict):
+def convert_test_type_to_difficulty_level(d):
     """
     对原本的单词库中的单词进行难度评级
-    :param words_dict: 存储了单词库pickle文件中的单词的字典
+    :param d: 存储了单词库pickle文件中的单词的字典
     :return:
     """
     result = {}
-    words_lst = list(words_dict.keys())  # in words_dict, we have test types (e.g., CET4,CET6,BBC) for each word
+    L = list(d.keys())  # in d, we have test types (e.g., CET4,CET6,BBC) for each word
 
-    for k in words_lst:
-        if 'CET4' in words_dict[k]:
+    for k in L:
+        if 'CET4' in d[k]:
             result[k] = 4  # CET4 word has level 4
-        elif 'OXFORD3000' in words_dict[k]:
+        elif 'OXFORD3000' in d[k]:
             result[k] = 5
-        elif 'CET6' in words_dict[k] or 'GRADUATE' in words_dict[k]:
+        elif 'CET6' in d[k] or 'GRADUATE' in d[k]:
             result[k] = 6
-        elif 'OXFORD5000' in words_dict[k] or 'IELTS' in words_dict[k]:
+        elif 'OXFORD5000' in d[k] or 'IELTS' in d[k]:
             result[k] = 7
-        elif 'BBC' in words_dict[k]:
+        elif 'BBC' in d[k]:
             result[k] = 8
 
     return result  # {'apple': 4, ...}
diff --git a/app/main.py b/app/main.py
index 6308f3d..4e3f829 100644
--- a/app/main.py
+++ b/app/main.py
@@ -63,7 +63,7 @@ def mark_word():
     '''
     if request.method == 'POST':
         d = load_freq_history(path_prefix + 'static/frequency/frequency.p')
-        lst_history = pickle_idea.dict_to_lst(d)
+        lst_history = pickle_idea.dict2lst(d)
         lst = []
         for word in request.form.getlist('marked'):
             lst.append((word, 1))
@@ -86,7 +86,7 @@ def mainpage():
         lst = f.get_freq()
         # save history
         d = load_freq_history(path_prefix + 'static/frequency/frequency.p')
-        lst_history = pickle_idea.dict_to_lst(d)
+        lst_history = pickle_idea.dict2lst(d)
         d = pickle_idea.merge_frequency(lst, lst_history)
         pickle_idea.save_frequency_to_pickle(d, path_prefix + 'static/frequency/frequency.p')
         return render_template('mainpage_post.html', lst=lst, yml=Yaml.yml)
@@ -96,8 +96,8 @@ def mainpage():
         number_of_essays = total_number_of_essays()
         d = load_freq_history(path_prefix + 'static/frequency/frequency.p')
         d_len = len(d)
-        lst = sort_in_descending_order(pickle_idea.dict_to_lst(d))
-        return render_template('mainpage_get.html',
+        lst = sort_in_descending_order(pickle_idea.dict2lst(d))
+        return render_template('mainpage_get.html', 
                                admin_name=ADMIN_NAME,
                                random_ads=random_ads,
                                d_len=d_len,
diff --git a/app/pickle_idea.py b/app/pickle_idea.py
index 4f193ff..45bd19a 100644
--- a/app/pickle_idea.py
+++ b/app/pickle_idea.py
@@ -10,7 +10,7 @@ import pickle
 from datetime import datetime
 
 
-def lst_to_dict(lst, d):
+def lst2dict(lst, d):
     ''' 
     Store the information in list lst to dictionary d. 
     Note: nothing is returned.
@@ -25,14 +25,14 @@ def lst_to_dict(lst, d):
             d[word] += freq
 
 
-def dict_to_lst(d):
-    return list(d.items())  # a list of (key, value) pairs
+def dict2lst(d):
+    return list(d.items()) # a list of (key, value) pairs
         
 
-def merge_frequency(list1, list2):
+def merge_frequency(lst1, lst2):
     d = {}
-    lst_to_dict(list1, d)
-    lst_to_dict(list2, d)
+    lst2dict(lst1, d)
+    lst2dict(lst2, d)
     return d
 
 
@@ -54,35 +54,33 @@ def save_frequency_to_pickle(d, pickle_fname):
     pickle.dump(d2, f)
     f.close()
 
-
-def unfamiliar(path, word):
-    f = open(path, "rb")
+def unfamiliar(path,word):
+    f = open(path,"rb")
     dic = pickle.load(f)
     dic[word] += [datetime.now().strftime('%Y%m%d%H%M')]
-    fp = open(path, "wb")
-    pickle.dump(dic, fp)
+    fp = open(path,"wb")
+    pickle.dump(dic,fp)
 
-
-def familiar(path, word):
-    f = open(path, "rb")
+def familiar(path,word):
+    f = open(path,"rb")
     dic = pickle.load(f)
-    if len(dic[word]) > 1:
+    if len(dic[word])>1:
         del dic[word][0]
     else:
         dic.pop(word)
-    fp = open(path, "wb")
-    pickle.dump(dic, fp)
+    fp = open(path,"wb")
+    pickle.dump(dic,fp)
 
 if __name__ == '__main__':
 
     lst1 = [('apple',2),  ('banana',1)]
     d = {}
-    lst_to_dict(lst1, d) # d will change
+    lst2dict(lst1, d) # d will change
     save_frequency_to_pickle(d, 'frequency.p') # frequency.p is our database
 
 
     lst2 = [('banana',2), ('orange', 4)]
     d = load_record('frequency.p')
-    lst1 = dict_to_lst(d)
+    lst1 = dict2lst(d)
     d = merge_frequency(lst2, lst1)
     print(d)
diff --git a/app/pickle_idea2.py b/app/pickle_idea2.py
index f3104a5..0da55bc 100644
--- a/app/pickle_idea2.py
+++ b/app/pickle_idea2.py
@@ -11,7 +11,6 @@
 import pickle
 from datetime import datetime
 
-
 def lst2dict(lst, d):
     ''' 
     Store the information in list lst to dictionary d. 
@@ -26,8 +25,7 @@ def lst2dict(lst, d):
         else:
             d[word] += dates
 
-
-def deleteRecord(path, word):
+def deleteRecord(path,word):
     with open(path, 'rb') as f:
         db = pickle.load(f)
     try:
diff --git a/app/user_service.py b/app/user_service.py
index 75971a6..2e5feed 100644
--- a/app/user_service.py
+++ b/app/user_service.py
@@ -93,7 +93,7 @@ def familiar(username, word):
 
 
 @userService.route("/<username>/<word>/del", methods=['GET', 'POST'])
-def delete_word(username, word):
+def deleteword(username, word):
     '''
     删除单词
     :param username: 用户名
@@ -181,7 +181,6 @@ def user_mark_word(username):
     else:
         return 'Under construction'
 
-
 def get_time():
     '''
     获取当前时间
diff --git a/app/wordfreqCMD.py b/app/wordfreqCMD.py
index 69065d6..e56ba0c 100644
--- a/app/wordfreqCMD.py
+++ b/app/wordfreqCMD.py
@@ -6,11 +6,10 @@
 import collections
 import string
 import operator
-import os, sys  # 引入模块sys，因为我要用里面的sys.argv列表中的信息来读取命令行参数。
+import os, sys # 引入模块sys，因为我要用里面的sys.argv列表中的信息来读取命令行参数。
 import pickle_idea
 
-
-def freq(s):
+def freq(fruit):
     '''
     功能： 把字符串转成列表。 目的是得到每个单词的频率。
     输入： 字符串
@@ -19,53 +18,54 @@ def freq(s):
     '''
 
     result = []
-    s = s.lower()  # 字母转小写
-    word_lst = s.split()  # 字符串转成list
-    c = collections.Counter(word_lst)
+    
+    fruit = fruit.lower() # 字母转小写
+    flst = fruit.split()  # 字符串转成list
+    c = collections.Counter(flst)
     result = c.most_common()
     return result
 
 
-def youdao_link(word):  # 有道链接
-    link = 'http://youdao.com/w/eng/' + word + '/#keyfrom=dict2.index'  # 网址
+def youdao_link(s): # 有道链接
+    link = 'http://youdao.com/w/eng/' + s + '/#keyfrom=dict2.index'# 网址
     return link
 
 
-def file_to_str(f_name):  # 文件转字符
-    f = open(f_name)  # 打开
-    f_str = f.read()  # 读取
-    f.close()  # 关闭
-    return f_str
+def file2str(fname):#文件转字符
+    f = open(fname) #打开
+    s = f.read()    #读取
+    f.close()       #关闭
+    return s
 
 
-def remove_punctuation(s):  # 这里是words_text是形参 (parameter)。函数被调用时才给words_text赋值。
-    special_characters = '\_©~<=>+-/[]*&$%^@.,?!:;#()"“”—‘’{}|'  # 把里面的字符都去掉
+def remove_punctuation(s): # 这里是s是形参 (parameter)。函数被调用时才给s赋值。
+    special_characters = '\_©~<=>+-/[]*&$%^@.,?!:;#()"“”—‘’{}|' # 把里面的字符都去掉
     for c in special_characters:
-        s = s.replace(c, ' ')  # 防止出现把 apple,apple 移掉逗号后变成 appleapple 情况
+        s = s.replace(c, ' ') # 防止出现把 apple,apple 移掉逗号后变成 appleapple 情况
     s = s.replace('--', ' ')
-    s = s.strip()  # 去除前后的空格
-
+    s = s.strip() # 去除前后的空格
+    
     if '\'' in s:
         n = len(s)
-        characters = ''  # 用来收集我需要保留的字符
-        for i in range(n):  # 只有单引号前后都有英文字符，才保留
+        t = '' # 用来收集我需要保留的字符
+        for i in range(n): # 只有单引号前后都有英文字符，才保留
             if s[i] == '\'':
                 i_is_ok = i - 1 >= 0 and i + 1 < n
-                if i_is_ok and s[i - 1] in string.ascii_letters and s[i + 1] in string.ascii_letters:
-                    characters += s[i]
+                if i_is_ok and s[i-1] in string.ascii_letters and s[i+1] in string.ascii_letters:
+                    t += s[i]
             else:
-                characters += s[i]
-        return characters
+                t += s[i]
+        return t
     else:
         return s
 
 
-def sort_in_descending_order(lst):  # 单词按频率降序排列
+def sort_in_descending_order(lst):# 单词按频率降序排列
     lst2 = sorted(lst, reverse=True, key=lambda x: (x[1], x[0]))
     return lst2
 
 
-def sort_in_ascending_order(lst):  # 单词按频率降序排列
+def sort_in_ascending_order(lst):# 单词按频率降序排列
     lst2 = sorted(lst, reverse=False, key=lambda x: (x[1], x[0]))
     return lst2
 
@@ -89,22 +89,22 @@ def make_html_page(lst, fname):  # 只是在wordfreqCMD.py中的main函数中调
 if __name__ == '__main__':
     num = len(sys.argv)
 
-    if num == 1:  # 从键盘读入字符串
+    if num == 1: # 从键盘读入字符串
         s = input()
-    elif num == 2:  # 从文件读入字符串
+    elif num == 2: # 从文件读入字符串
         fname = sys.argv[1]
-        s = file_to_str(fname)
+        s = file2str(fname)
     else:
         print('I can accept at most 2 arguments.')
-        sys.exit()  # 结束程序运行， 下面的代码不会被执行了。
+        sys.exit()# 结束程序运行， 下面的代码不会被执行了。
 
-    s = remove_punctuation(s)  # 这里是s是实参(argument)，里面有值
+    s = remove_punctuation(s) # 这里是s是实参(argument)，里面有值
     L = freq(s)
     for x in sort_in_descending_order(L):
-        print('%s\t%d\t%s' % (x[0], x[1], youdao_link(x[0])))  # 函数导出
+        print('%s\t%d\t%s' % (x[0], x[1], youdao_link(x[0])))#函数导出
 
     # 把频率的结果放result.html中
-    make_html_page(sort_in_descending_order(L), 'result.html')
+    make_html_page(sort_in_descending_order(L), 'result.html') 
 
     print('\nHistory:\n')
     if os.path.exists('frequency.p'):
@@ -112,9 +112,12 @@ if __name__ == '__main__':
     else:
         d = {}
 
-    print(sort_in_descending_order(pickle_idea.dict_to_lst(d)))
+    print(sort_in_descending_order(pickle_idea.dict2lst(d)))
 
     # 合并频率
-    lst_history = pickle_idea.dict_to_lst(d)
+    lst_history = pickle_idea.dict2lst(d)
     d = pickle_idea.merge_frequency(L, lst_history)
     pickle_idea.save_frequency_to_pickle(d, 'frequency.p')
+
+
+
diff --git a/requirements.txt b/requirements.txt
index 2210969..338b71c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-Flask==2.2.3
+Flask==1.1.2
 selenium==3.141.0
 PyYAML~=6.0
 pony==0.7.16