diff --git a/docs/string.md b/docs/string.md
index b3ba685..1daf7af 100644
--- a/docs/string.md
+++ b/docs/string.md
@@ -450,7 +450,7 @@ var y = 2;
 
 var obj = {x: 1, y: 2};
 `${obj.x + obj.y}`
-// 3
+// "3"
 ```
 
 模板字符串之中还能调用函数。