you should do=you need to do=?

you should do=you need to do=? 是you need do what you should do 还是you need to do what you sh Do you need to do homework?why? wat do you need to buy? you,do,to,your,homework,need,(.) Who else do you need to buy ( Do you need so that too to You need to do it ,___ ___? what do you need What do you need? do you need to do… 和need you do…?怎么区分?如何判断疑问词用do还是need? What should you do to keep health