情态动词在句中放在谓语动词之前,谓语动词前若有助动词,则在助动词之前,疑问句中,情态动词则在主语之前.
I can see you.Come here.
我能看见你,过来吧.
He must have been away.
他一定走了.
What can I do for you?
我能帮你吗?
How dare you treat us like that!
你怎能那样对待我们!