谁能剖析一下 be going todo/be todo/be doing

谁能剖析一下 be going todo/be todo/be doing be used to doing和be used todo什么区别 Allow sb to do 和be allowed todo allow doing 造句 I want to be an artist so how am i going todo it? 用should be allowed todo 造句关于老师的 todo try todo/ doing stick to doing,todo? students should be allowed to take time todo things like tha be going to,be about to,be doing 的区别 用DO ,TODO,doing造句 doing与 todo的区别