对await部分添加新的描述

JS/JS-ch.md

@@ -1426,7 +1426,7 @@ console.log('1', a) // -> '1' 1
 对于以上代码你可能会有疑惑，这里说明下原理
 
 - 首先函数 `b` 先执行，在执行到 `await 10` 之前变量 `a` 还是 0，因为在 `await` 内部实现了 `generators` ，`generators` 会保留堆栈中东西，所以这时候 `a = 0` 被保存了下来
-- 因为 `await` 是异步操作，所以会先执行 `console.log('1', a)`
+- 因为 `await` 是异步操作，遇到`await`就会立即返回一个`pending`状态的`Promise`对象，暂时返回执行代码的控制权，使得函数外的代码得以继续执行，所以会先执行 `console.log('1', a)`
 - 这时候同步代码执行完毕，开始执行异步代码，将保存下来的值拿出来使用，这时候 `a = 10`
 - 然后后面就是常规执行代码了
 

JS/JS-en.md

@@ -1291,7 +1291,7 @@ console.log('1', a) // -> '1' 1
 You may have doubts about the above code, here we explain the principle:
 
 - First the function `b` is executed. The variable `a` is still 0 before execution  `await 10`, Because the `Generators` are implemented inside `await` and  `Generators` will keep things in the stack, so at this time `a = 0` is saved
-- Because `await` is an asynchronous operation, `console.log('1', a)` will be executed first.
+- Because `await` is an asynchronous operation,  it will immediately return a `pending` state `Promise` object when it encounter `await`, and temporarily returning control of the execution code, so that the code outside the function can continue to be executed. `console.log('1', a)` will be executed first.
 - At this point, the synchronous code is completed and asynchronous code is started. The saved value is used. At this time, `a = 10`
 - Then comes the usual code execution