diff --git a/TinySTL/Detail/Vector.impl.h b/TinySTL/Detail/Vector.impl.h
index 9e1c3f1df43c94377aa467c85bb2f6eacdec31c1..d2cb2e8e060955f9ca06fd3c6cc7a29df7fcd2ea 100644
--- a/TinySTL/Detail/Vector.impl.h
+++ b/TinySTL/Detail/Vector.impl.h
@@ -141,12 +141,13 @@ namespace TinySTL{
 		InputIterator last,
 		std::false_type){
 		difference_type locationLeft = endOfStorage_ - finish_; // the size of left storage
-		difference_type locationNeed = last - first;
+		difference_type locationNeed = distance(first, last);//last - first;
 
 		if (locationLeft >= locationNeed){
 			iterator tempPtr = end() - 1;
 			for (; tempPtr - position >= 0; --tempPtr){//move the [position, finish_) back
-				*(tempPtr + locationNeed) = *tempPtr;
+				//*(tempPtr + locationNeed) = *tempPtr;//bug
+				construct(tempPtr + locationNeed, *tempPtr);
 			}
 			TinySTL::uninitialized_copy(first, last, position);
 			finish_ += locationNeed;
@@ -165,7 +166,8 @@ namespace TinySTL{
 		if (locationLeft >= locationNeed){
 			auto tempPtr = end() - 1;
 			for (; tempPtr - position >= 0; --tempPtr){//move the [position, finish_) back
-				*(tempPtr + locationNeed) = *tempPtr;
+				//*(tempPtr + locationNeed) = *tempPtr;//bug
+				construct(tempPtr + locationNeed, *tempPtr);
 			}
 			TinySTL::uninitialized_fill_n(position, n, value);
 			finish_ += locationNeed;
diff --git a/TinySTL/String.h b/TinySTL/String.h
index 5d81ca17662c2f9fc53a36539df44731ce0b75a7..ec83564f02e5ffed2088acd47668cb4c91fa14f2 100644
--- a/TinySTL/String.h
+++ b/TinySTL/String.h
@@ -244,7 +244,7 @@ namespace TinySTL{
 	template <class InputIterator>
 	string::iterator string::insert(iterator p, InputIterator first, InputIterator last){
 		auto lengthOfLeft = capacity() - size();
-		size_t lengthOfInsert = last - first;
+		size_t lengthOfInsert = distance(first, last);
 		if (lengthOfInsert <= lengthOfLeft){
 			for (iterator it = finish_ - 1; it >= p; --it){
 				*(it + lengthOfInsert) = *(it);