情态动词• 一）情态动词的含义：• 情态动词表示说话人对某一动作或状态的的态度，认为“可能”，“应当”，“必要”等。• 情态动词不能单独作谓语，必须和不带 to 的动词不定式连用。情态动词没有人称和数的变化。• （二）几种主要的情态动词： 1. 表示可能的情态动词 : may, might, could , can, must, • （ 1 ） may , might, could 都可以用来表示可能性，意思是“可能”，“也许”，它既表示现在的可能性，也表示将来的可能性 They may be waiting at the station.• You’d better take an umbrella. It might rain tonight.• The phone is ringing. It could be Tim.• I haven’t decided where to spend my holidays. I may go to Ireland.• The bus doesn’t always come on time. We might have to wait a few minutes. ： • 它们的否定形式是 : • may not, might not 意思是 “可能不” • I’m not sure whether I can lend you any money. I may not have enough money.• It might not be true.• Ann may not come to the party tonight. She isn’t well.• （ 2 ） may, might, could 后面接 have done 的形式，表示一种过去的可能性，是对过去动作的推测。• He may have left yesterday.• ——I wonder why he was in such a bad mood yesterday.• ——He may not have been feeling well.• He might have known about it.• Tom could have taken it; he was here along yesterday.• • （ 3 ） must 也表示比较有把握的推测 , 是有一定事实基础之上的判断 :• The police are stopping all cars. They must be looking for the escaped prisoner.• The light is on. They must be at home.• You have been traveling all day. You must be very tired.• 4 ） can 一般用在否定和疑问句中表示可能性 . • You have just had lunch. You can’t be hungry already.• They haven’t lived here for very long. They can’t know many people.• That couldn’t be John. I know he’s still out of town.• There is someone outside.—...
