why not do sth 等于why dont you do sth 为什么后面要加动词原形呢不是to do 呢 请回答具体一些

why not do sth.=why don't you do sth.还等于什么 是why not do sth.还是why not doing sth. why not doing sth还是why not do sth还是why not to do sth why not do sth 还是doing sth 用why not do sth造句 why not do sth sb放哪? why not do sth ?的用法 why not to do sth对吗?waiting why do not do sth与why not do sth有什么区别? 是Why not to do sth还是Why not do sth? 那个语法是why not to do Sth还是why not do Sth why not do sthwhy not to do sthwhich is right why not等于why()() why not后面是doing sth还是 to do sth why not doing sth和 why not do sth的区别 Why not do sth.=Why don't you do sth.=什么? 是why bot do sth.还是why not to do sth. Why don't do sth和 why not do sth有什么区别?