why not 和why dont you 有什么区别？

why not 和why don't 有什么区别啊! why you must和why must you有什么区别? why don't you…… 与why not you……有什么区别 why not do和why not to do有什么区别?要尽快! Why not do 和 Why don't do 什么区别 Why not,Why don't.有什么区别? why do not和why not有什么不同? Why don’t和Why not有啥区别? Why don't do sth和 why not do sth有什么区别? why won't you和why don't you有什么区别吗 Why are you drinking?和Why do you drink?有什么区别? why you give up 和why do you give up 有什么区别