why not do还是why not doing?老师上课讲的是why not doing,可是我做课外题时答案是why not do,谁知道到底是什么啊

why not +doing还是do why not do还是why not to do why not doing sth还是why not do sth还是why not to do sth why not to do 还是why not doing 是why not do sth.还是why not doing sth. why not to do还是why not doing why not sb +do还是to do why not do it Why do not want why not do句子 why not 后跟do 还是doing? why not do sth 还是doing sth Why not 后面+doing 还是to do? why not do还是why not to do?都把我弄蒙了 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 you still do not come还是why you do not still come why not后加do还是doing还是to do?