Update solution.md

Author: leviding

1-js/05-data-types/08-weakmap-weakset/02-recipients-when-read/solution.md

@@ -1,15 +1,15 @@
 
-我们使用 `WeakMap` 保存日期：
+我们可以使用 `WeakMap` 保存日期：
 
-```js run
+```js
 let messages = [
-    {text: "Hello", from: "John"},
-    {text: "How goes?", from: "John"},
-    {text: "See you soon", from: "Alice"}
+  {text: "Hello", from: "John"},
+  {text: "How goes?", from: "John"},
+  {text: "See you soon", from: "Alice"}
 ];
 
 let readMap = new WeakMap();
 
 readMap.set(messages[0], new Date(2017, 1, 1));
-// Date 对象我们将会稍后学习
+// 我们稍后将学习 Date 对象
 ```