why not do sth

why not do sth why not +do sth why not doing sth还是why not do sth还是why not to do sth why not to do sth对吗?waiting why not do sth ?的用法 why not do sth sb放哪? 用"why not do sth"造句 why not do sth?怎么回答 why do not do sth与why not do sth有什么区别? Why not doing sth.make sb.to do sth. why not后面是doing sth还是 to do sth 那个语法是why not to do Sth还是why not do Sth