why don't you ; why not ; what about 三者的区别与用法

网友回答

why don't you 你为什么不.
why not 何不.
what about 那么,（这个呢?）
请看例句：The stores here open on weekends.Why don't you do it on Sunday when you don't have to attend school?
我们这儿的店周末营业.你为什么不（等到）周日去?周日你不必上学.
You know the first solution didn't work.Why not try a different way?
你（已）知道第一个方法不起作用,何不尝试另一个解决方式?
That didn't do any good.What about doing it this way instead?
那（个做法）没有任何效果,那么,这样做怎么样呢?
======以下答案可供参考======
供参考答案1:
why don't +sb.（在why don't you 后面可加动词原形。）
why not后面只能加动词原形，不能加sb.
what about=how about 它们后面加动词的ing形式。
供参考答案2:
三个都是表示提出建议
Why don't you do sth?你（们）为什么不做某事呢？
Why not do sth?为什么不做某事呢？
What about doing sth?做某事怎样？