情态动词can（能够）, must（必须）, may（可以）

结构：主语+can/must/may+动词原型

He can make the tea.

Sally can air the room.

We can speak English.

★变疑问句将情态动词移到句首

Can he make the tea?

Can Sally air the room?

Can we speak English?

★变否定句在情态动词后面加not

He cannot make the tea.

Sally cannot air the room.

We cannot speak English.

★肯定回答及否定回答

Yes, he can. No, he cannot.

Yes, she can. No, she cannot.

Yes, we can. No, we cannot.

★特殊疑问句：

What can you do?

注意：情态动词的句子没有第三人称单数的变化，不要在情态动词或动词后面加S。