diff --git a/TinySTL/AVLTree.h b/TinySTL/AVLTree.h
index f3ce4de..bce8948 100644
--- a/TinySTL/AVLTree.h
+++ b/TinySTL/AVLTree.h
@@ -45,7 +45,7 @@ namespace TinySTL{
 		void insert(const T& val);
 		template<class Iterator>
 		void insert(Iterator first, Iterator last);
-		void erase(const T& val);//todo
+		void erase(const T& val);
 
 		size_t height()const{ return getHeight(root_); }
 		size_t size()const{ return size_; }
diff --git a/TinySTL/BinarySearchTree.h b/TinySTL/BinarySearchTree.h
index debd66e..300f5f3 100644
--- a/TinySTL/BinarySearchTree.h
+++ b/TinySTL/BinarySearchTree.h
@@ -87,7 +87,7 @@ namespace TinySTL{
 	};//end of bst class
 	template<class T>
 	size_t binary_search_tree<T>::height_aux(node *p)const{
-		TinySTL::queue<node *> q, level;
+		TinySTL::queue<node *> q/*存放下一层的node*/, level/*存放当前层的node*/;
 		size_t nlevel = 0;
 		if (p != 0){
 			level.push(p);
@@ -95,7 +95,7 @@ namespace TinySTL{
 			while (!(q.empty() && level.empty())){
 				if (level.empty()){
 					++nlevel;
-					while (!q.empty()){
+					while (!q.empty()){//当前层为空，将下一层的node全部转移至当前层
 						level.push(q.front());
 						q.pop();
 					}