diff --git a/PythonLanguage/12. 函数与Lambda表达式.md b/PythonLanguage/12. 函数与Lambda表达式.md
index 88ad37c..20d222e 100644
--- a/PythonLanguage/12. 函数与Lambda表达式.md	
+++ b/PythonLanguage/12. 函数与Lambda表达式.md	
@@ -36,16 +36,6 @@ temp = printme('hello') # hello
 print(temp)  # None
 ```
 
-【例子】
-```python
-def add(a, b):
-    print(a + b)
-
-
-add(1, 2)  # 3
-add([1, 2, 3], [4, 5, 6]) # [1, 2, 3, 4, 5, 6]
-```
-
 ### 函数文档
 
 ```python
@@ -401,18 +391,16 @@ outer()
 
 【例子】`n! = 1 x 2 x 3 x ... x n`
 
-++循环++
+
 
 ```python
+# 利用循环
 n = 5
 for k in range(1, 5):
     n = n * k
 print(n)  # 120
-```
 
-
-++递归++
-```python
+# 利用递归
 def factorial(n):
     if n == 1:
         return 1
@@ -424,9 +412,10 @@ print(factorial(5)) # 120
 
 【例子】斐波那契数列 `f(n)=f(n-1)+f(n-2), f(0)=0 f(1)=1`
 
-++循环++
+
 
 ```python
+# 利用循环
 i = 0
 j = 1
 lst = list([i, j])
@@ -437,11 +426,8 @@ for k in range(2, 11):
     j = k
 print(lst)  
 # [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
-```
 
-++递归++
-
-```python
+# 利用递归
 def recur_fibo(n):
     if n <= 1:
         return n
@@ -463,6 +449,9 @@ import sys
 sys.setrecursionlimit(1000)
 ```
 
+有关递归的详细介绍参见：
+- [利用python解决汉诺塔问题？](https://mp.weixin.qq.com/s?__biz=MzIyNDA1NjA1NQ==&mid=2651010966&idx=1&sn=57c9c6a05cfeaafc6bb88eaee54550a3&chksm=f3e3500ec494d918edc37c3e23997d0fc330152029e7140b82437f453ec9e7bf8d0c500a500d&token=523711417&lang=zh_CN#rd)
+
 ---
 ## 2. Lambda 表达式
 
@@ -598,12 +587,17 @@ print(apply_to_list(lambda x: sum(x) / len(x), lst))
 # 3.0
 ```
 
+
 ---
 **参考文献**：
 - https://www.runoob.com/python3/python3-tutorial.html
 - https://www.bilibili.com/video/av4050443
 - https://mp.weixin.qq.com/s/gKhXS8JVU8dZBHJF7sIFsw
 
+
+
+
+
 ---
 **练习题**：