为什么不能说what does she doing?

为什么不能说what does she doing? what does she doing? 为什么是what is she doing for vacation.而不是what does she do for v what's she doing和what does she doing有什么不同? what does he mean为什么不能说what is he mean what does she like和 what does she like doing区别? what does he like doing?为什么用doing What does Mary doing?She is eating.错在哪 英语语法,实意动词作谓语要用助动词does,那为什么这句话（What`s she doing?）不是What does Does she like salad 为什么不能把Does 换成Is What does she do in the morning 和 What is she doing now 前句用 （歌手）what is she doing?what does she do?（用英语回答）