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--- a/04-0/README.md
+++ b/04-1/README.md
@@ -1,3 +1,3 @@
-# 第四章 循环结构
+# 第四章 作业（循环结构）
 
 > 作业时间： 2021-11-03 22:56:00 至 2021-11-26 23:55:00
diff --git a/README.md b/README.md
index 0a75e85..bce7671 100644
--- a/README.md
+++ b/README.md
@@ -33,14 +33,14 @@ A repo to record my study life.
   - [2. 计算个人所得税](https://github.com/xtaodada/C-study/tree/master/03-1/2)
   - [3. 判断三角形](https://github.com/xtaodada/C-study/tree/master/03-1/3)
   - [4. 查询水果单价](https://github.com/xtaodada/C-study/tree/master/03-1/4)
-- [第四章 循环结构](https://github.com/xtaodada/C-study/tree/master/04-0)
-  - [1. 【循环结构】用do---while语句实现循环，计算1+2+3+…+1000](https://github.com/xtaodada/C-study/tree/master/04-0/1)
-  - [2. 【循环结构】用for语句实现循环，计算1+1/2+1/3+1/4+...1/100 的和](https://github.com/xtaodada/C-study/tree/master/04-0/2)
-  - [3. 【循环结构】要求输出100～200之间的不能被3整除的前10个和最后10个整数](https://github.com/xtaodada/C-study/tree/master/04-0/3)
-  - [4. 【循环结构】使用循环的嵌套来输出以下4*5的矩阵](https://github.com/xtaodada/C-study/tree/master/04-0/4)
-  - [5. 【循环结构】输入一个大于3的整数n，判定它是否素数(prime，又称质数)](https://github.com/xtaodada/C-study/tree/master/04-0/5)
-- [实验四 循环结构（2学时）](https://github.com/xtaodada/C-study/tree/master/04-1)
-  - [1. 【循环结构】求Sn=1+12+123+1234+… 之值，其中，累加项n从键盘输入](https://github.com/xtaodada/C-study/tree/master/04-1/1)
-  - [2. 【循环结构】找最大最小整数](https://github.com/xtaodada/C-study/tree/master/04-1/2)
-  - [3. 【循环结构】双重循环计算给定公式的值](https://github.com/xtaodada/C-study/tree/master/04-1/3)
-  - [4. 【循环结构】求两个正整数之间的水仙花数](https://github.com/xtaodada/C-study/tree/master/04-1/4)
+- [实验四 循环结构（2学时）](https://github.com/xtaodada/C-study/tree/master/04)
+  - [1. 【循环结构】求Sn=1+12+123+1234+… 之值，其中，累加项n从键盘输入](https://github.com/xtaodada/C-study/tree/master/04/1)
+  - [2. 【循环结构】找最大最小整数](https://github.com/xtaodada/C-study/tree/master/04/2)
+  - [3. 【循环结构】双重循环计算给定公式的值](https://github.com/xtaodada/C-study/tree/master/04/3)
+  - [4. 【循环结构】求两个正整数之间的水仙花数](https://github.com/xtaodada/C-study/tree/master/04/4)
+- [第四章 作业（循环结构）](https://github.com/xtaodada/C-study/tree/master/04-1)
+  - [1. 【循环结构】用do---while语句实现循环，计算1+2+3+…+1000](https://github.com/xtaodada/C-study/tree/master/04-1/1)
+  - [2. 【循环结构】用for语句实现循环，计算1+1/2+1/3+1/4+...1/100 的和](https://github.com/xtaodada/C-study/tree/master/04-1/2)
+  - [3. 【循环结构】要求输出100～200之间的不能被3整除的前10个和最后10个整数](https://github.com/xtaodada/C-study/tree/master/04-1/3)
+  - [4. 【循环结构】使用循环的嵌套来输出以下4*5的矩阵](https://github.com/xtaodada/C-study/tree/master/04-1/4)
+  - [5. 【循环结构】输入一个大于3的整数n，判定它是否素数(prime，又称质数)](https://github.com/xtaodada/C-study/tree/master/04-1/5)