1)情態(tài)動(dòng)詞can(能夠)， must(必須)， may(可以)

結(jié)構(gòu)：主語(yǔ)+can/must/may+動(dòng)詞原型

He can make the tea.

Sally can air the room.

We can speak English.

★變疑問(wèn)句將情態(tài)動(dòng)詞移到句首

Can he make the tea?

Can Sally air the room?

Can we speak English?

★變否定句在情態(tài)動(dòng)詞后面加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.

★特殊疑問(wèn)句：

What can you do?

(必背)

注意：情態(tài)動(dòng)詞的句子沒(méi)有第三人稱(chēng)單數(shù)的變化，不要在情態(tài)動(dòng)詞或動(dòng)詞后面加S。

Must/have to的區(qū)別

must 表示必須，是主觀上覺(jué)得應(yīng)該做，have to是不得不，是由于客觀條件逼迫的必要要做

must 只能用在表示現(xiàn)在和將來(lái)的句子里，而have to do可以用在任何時(shí)態(tài)must, may, might表示猜測(cè)：

must do 表示對(duì)現(xiàn)在事實(shí)的猜測(cè)

must have done表示對(duì)過(guò)去事實(shí)的猜測(cè)

must have been doing 表示對(duì)過(guò)去正在進(jìn)行的事實(shí)的猜測(cè)

may/might do, may/might have done表示沒(méi)有任何事實(shí)依據(jù)的猜測(cè)，might的可能性更小。

can’t/couldn’t 表示不可能