diff --git a/problems/0098.验证二叉搜索树.md b/problems/0098.验证二叉搜索树.md
index a271b977..cf8651f3 100644
--- a/problems/0098.验证二叉搜索树.md
+++ b/problems/0098.验证二叉搜索树.md
@@ -338,7 +338,7 @@ class Solution {
 
 Python：
 
-**递归** - 利用BST中序遍历特性
+**递归** - 利用BST中序遍历特性,把树"压缩"成数组
 ```python
 # Definition for a binary tree node.
 # class TreeNode:
@@ -362,7 +362,7 @@ class Solution:
             
         def __is_sorted(nums: list) -> bool: 
             for i in range(1, len(nums)): 
-                if nums[i] <= nums[i - 1]:
+                if nums[i] <= nums[i - 1]: # ⚠️ 注意: Leetcode定义二叉搜索树中不能有重复元素
                     return False
             return True
         
@@ -370,8 +370,11 @@ class Solution:
         res = __is_sorted(candidate_list)
         
         return res
+```
 
-# 简单递归法
+**递归** - 
+
+```python
 class Solution:
     def isValidBST(self, root: TreeNode) -> bool:
         def isBST(root, min_val, max_val):