第13讲情态动词

1、第13讲情态动词1.英语情态动词 can ; could; may; might; will; would; shall; should; must; need;have to; ought to.情态动词没有人称，数的变更，即情态动词加do.A 比较 can 和 be able to1） can /could表示能力；可能（过去时用could）,只用于现在式和从前式（could）。be able to能够用于各种时态。They will be able to tell you the news soo n. 他很快就能告诉你消息了。2）表示成功地做了某事时，只能用 was/were able

2、 to， 不能用could。He was able to flee Europe before the war broke out.=He man aged to flee Europe before the war broke out.could不表示时态内容来自1 ）提出委婉的恳求，（留神在答复中不可用could ）。-Could I have the televisi on on?-Yes, you can. / No, you can't.2）在否定，疑问句中表示推测或猜疑He could n't be a bad man.B比较 may和 might内容来自1）表示请

3、求允许；表示 推测；He might be at home.May I come in ?初中英语情态动词注意：might表示推测时，不表示时态。只是可能性比may小。may/might as well，后面 do, 意为"不妨"If that is the case, we may as well try.Petercome with us toni ght, but he isn't very sure yet.A. mustB. may C. canD. willC 比较 have to 和 must1. have to表示客观的须要，must表示谈话人主观上

4、的看法，既主观上的必要。My brother was very ill, so I had to call the doctor in the middle of the ni ght.He said that they must work hard.2. have to有人称、数、时态的变化，而must只有一种形式。He had to look after his sister yesterday.3. 在否定构造中：don't have to 表示"不必"must n't表示"禁止"，You don't have to tel

5、l him about it.You must n't tell him about it.4. must表示推测1) must用在肯定句中表示较有把握的推测，意为"一定"。2) must表对现在的状态或现在正产生的事件的推测时，must后面通常接系动词be的本相或举动动词的进行式。You have worked hard all day. You must be tired.内容来自He must be worki ng in his office.3) 否定推测用can't。If Tom did n't leave here un til fiv

6、e o'clock, he can't be home yet.D should 跟 ought to ； ought to 在语气上比 should 要强。should和ought to都为"应当”的意思，可用于各种人称。-Ought he to go?-Yes. I think he ought to.表示命令时，语气由 should (应该)、had better最好)、must (必须)渐强E . had better 表示"最好"had better 它后面要跟动词原形had better do sth/ had better n ot

7、do sthIt is pretty cold. You'd better put on my coat. 内容来自She'd better not play with the dog.F. will 和 would1)would like ； Would like to do = want to 想要，为固定搭配。Would you like to go with me? 表示委婉语气2) Will you ？ Would you like?Would you like some cake?G 情态动词的回答万式 问句Need I go home now ? Must you

8、 do your work now?肯定回答Yes , you must. /Yes, I must/否定回答No , you n eed n'tNo, I don't have to. / needn '1)-Could I borrow your dict ion ary?-Yes, of course, you.A. mightB. willC. can D. should2) -Shall I tell John about it?-No, you.I've told him already.A. need n'tB. would n'tC. must n'tD. should n't3) -Don't forget to come to my birthday party tomorrow.-A. I don'tB. I won'tC. I ca n'tD. I have n't 内容来H 比较 need 和 dare m两词既可做实义动词用，又可做情态动词用。作为情态动词，两者