如果含有Be动词,直接把Be动词提前;
如果含有情态动词,直接把情态动词提前;
如果含有行为动词,需要借助助动词do,dose(三单),did(过去式)完成,行为动词用原形。
例句:1.It's a dog.
Is it a dog?
2.He can play baseball.
Can he play baseball?
3.They play football.
Do they play football?
有BE动词或者情态动词的,直接提前,没有的加助动词补充!