高三英语复习 情态动词讲义

情态动词情态动词有：can (could), may (might), shall (should), will (would), must, have to, need, dare (dared), ought to, used to. 情态动词无人称和数的变化，不能独立使用，它与其后面的动词原形合成谓语。情态动词的具体用法如下：1 can1）表示能力 能，能够A computer can not think for itself, it must be told what to do.2）表示可能（理论上或是逻辑判断上）。The temperature can fall to 60, that is 60 below freezing. 气温可降至60，也就是零下60。He cant (couldnt) have enough money for a new car. 他不可能有足够的钱买新车。3）表示惊异、怀疑、不相信的态度。（主要用在否定句、疑问句或惊叹句中）“是否有可能”_ it be true that your bike was stolen again? (Is it possible?)How _ you be so careless!_ anyone be such a fool as to believe that?4）用来表示一种可能出现的事情，或表示某事、某物、某人偶然或通常有做出什么事的倾向。通常（但并非总是）指不愉快的事情。或表示某些特殊情况下的可能性,客观的可能性Our house is on the top of a hill, and in winter the winds _ be pretty cold. The World Wide Web is jokingly called the World Wide Wait, for sometimes it can be very slow.It can be very cold in the mountains.Accidents can happen on such rainy days.I would rather go shopping alone than go with her because she can be rather tiresome at times.比较：Driving on these roads _ be a very nerve-racking business.Driving on this icy road _ be dangerous today.5）比较委婉客气地提出问题或陈述看法。Can (Could) you lend me a hand? 帮我一把好吗？Im afraid we couldnt give you an answer today. 恐怕我们今天不能给你答复。6) can表示能力时，还可用be able to代替。如：I could / was able to play chess when I was six.但be able to 可用于各种时态Ill not be able to come this afternoon.I have been able to do the work.I hope to be able to do the work.区别：Something was wrong with my car, but I _ drive it to the garage.= Something was wrong with my car, but I _ drive it to the garage.= Something was wrong with my car, but I _ drive it to the garage.be able to 可以表示经过努力或克服了困难之后做成了某事，相当于manage to do , succeed in doing 7)表推测 cant have done 表示对过去发生的事情的否定推测She cant be at home now, for the lights are all out.It cant have rained last night, for the ground is dry.8) can 的习惯用法It is as good as can be.不能再好了。One cannot be too careful to drive a car./ in driving a car.One can not but be moved by his noble deeds.人们不能不为他那高尚的行为所感动。cant/couldnt help doingcant/couldnt help to do2. could1) can 的过去式I could speak a little Japanese when I was at college but now I have forgotten all of them except a few words.2) 客气的请求Could I borrow your dictionary?Yes/Of course, you can.3) could用在肯定句中表示一种比较婉转的怀疑。His story _ be true, but I hardly think it is.4) could have done表示对过去能做而未做的事感到惋惜、遗憾。意思是“本可以；可能已经做了某事”I stayed at a hotel while in New York._ Oh, did you? You could have stayed with Barbara.5) couldnt have done”表示对过去情况的推测，意思是“不可能做了”。例如：He could not have seen the film because he knew nothing about it.3.may,might1）表示许可，might可以指过去时间，也可指现在时间，语气更委婉。You may take whatever you like. 你喜欢什么就拿什么。May (Might) I ask for a photo of your baby? 我可以要一张你宝宝的照片吗？May I use your car? No, you mustnt.(Sorry, but Im using it now./Youd better not.)在回答以may引起的问句时，多避免用这个词，而用其它方式，如Yes, please. / Certainly. / Please dont ./ Youd better not. / No, you mustnt.等，以免显得太严峻或不客气。2）表示可能（可能性较 must 和 can 小）。might可以指过去时间，也可以指现在时间，但语气更加不肯定。Peter may come with us tonight , but he isnt very sure yet.They might be having a meeting, but Im not sure. 他们有可能在开会，不过我不肯定。3) may/might have done表示对过去的推测。Its too late. He may have gone to bed.Yesterday ,Jane walked away from the discussion. Otherwise ,she might have said something she would regret later.4. shall1）表征询意见，用于第一、第三人称疑问句。Shall I get you some tea? 我给你点茶好吗？2）表说话人的意愿，有“命令、允诺、警告、威胁”等意思，用于第二、第三人称陈述句。You shall do as I say. 按我说的做。（命令）You shall have my answer tomorrow. 你明天可以得到我的答复。（允诺）You shall fail if you dont work hard. (警告)3)当宣布法律、规定时It has been announced that candidates shall remain in their seats until all the papers have been collected.(规则或规定)5. should1）表义务。意为“应该”（某件事宜于做），用于各种人称。You should be polite to your teachers. 你对老师应该有礼貌。You shouldnt waste any time. 你不应该浪费时间。2）表推测，意为“想必一定、照说应该、估计”等。The film should be very good as it is starring first-class actors. 这部新电影是一流演员主演的，估计拍得很好。They should be home by now. 照说他们现在应当已经到家了。- When can I come for the photos? I need them tomorrow afternoon.- They should be ready by 12:00.3). 在名词性从句中表感情，即说话人认为应该如此。例如：It is natural that students should study hard.4). 表示“竟然”Swine flue should have nothing to do with pigs.5). should have done 表示过去应该做而未做某事。含有惋惜、责备的意味。例如：We should have studied last night, but we went to the concert instead.6. will1）表意愿，用于各种人称陈述句。None is so blind as those who wont see. 不愿看的人眼最瞎。If you will read the book, Ill lend it to you. 如果你愿意读这本书，我会把它借给你。2）表示询问对方的意愿或向对方提出请求，用于第二人称的疑问句中Will you close the window? Its a bit cold. 请你把窗户关上好吗？有点冷。Wont you drink some more coffee? 再来一点咖啡好吗？3）表示某种倾向或习惯性动作。Fish will die out of water. 鱼离开水就不能活。The boy will sit there hour after hour looking at the traffic go by. 那男孩常常坐在那里好几个钟点，看着车辆行人通过。4) 表功能The door/window wont open.7.would1）表意愿。They would not let him in because he was poorly dressed. 他们不让他进去因为他衣着破旧。2）表委婉地提出请求、建议或看法，比 will 客气。Would you like another glass of beer? 再来杯啤酒好吗？They wouldnt have anything against it. 他们不会有什么反对意见。3）表过去反复发生的动作或过去的一种倾向。Every time she was in trouble, she would go to him for help. 她每遇到麻烦都会向她求助。他告诉我盒子打不开了。Whenever I passed his house I would see him standing under the big tree.8. must1）表示义务或强烈的劝告，意为“必须”，否定式表示“禁止”、“不准”。在回答 must 的问句时， 否定回答用 neednt 或 dont have to .。We must do everything step by step. 我们一切都必须循序渐进地做。-Must we hand in our exercisebooks now? 我们现在就要交练习本吗？-No, you neednt. / No, you dont have to. 不必。2）表示对现在情况的推测用“must + 动词原形”。意为“想必、准是、一定”等，只用于肯定句。He must be ill. He looks so pale. 他准是病了。他的脸色苍白。Shes wearing a diamond necklace. She must have a lot of money.她戴着钻石项链，一定很有钱。3）对过去情况的猜测用“must+ have +过去分词”。例如：It must have rained last night, for the ground is wet.4) 表示“偏要、硬要”做某事How old are you, Madam?If you must know, Im twice my sons age.9. ought to 1）表义务，意为“应该”（因责任、义务等该做），口气比should稍重。You are his father. You ought to take care of him. 你是他父亲，应当管他。You oughtnt to smoke so much. 你不应该抽这么多烟。2）表推测，暗含很大的可能，语气较弱。Han Mei ought to know his telephone number. 韩梅该知道他的电话号码。Theres a fine sunset; it ought to be a fine day tomorrow. 今天有晚霞，明天应该是个好天。3) ought to have done 表示过去应该做而未做的事情。例如：You ought to have helped him. (but you didnt)1、can ,和be able to can 和be able to 在表示“能力”时意思相同，但在用法上有区别。1). can 表示主观能力， be able to 表示客观能力。can 表示有这种能力或机会，be able to 则表示经历一番艰难后能够做成某事。例如：I can drive , but Im not able to drive now because Im drunk.The fire spread through the hotel very quickly but everyone was able to get out.2). can只有两种时态形式，现在式can和过去式could，而be able to有多种时态形式。Mary can play the piano. She has been able to play it since she was 5. 3). be able to 可用于动词不定式和动名词结构中， can 不能。例如：I regret not being able to take his advice.2. must和 have tomust表示主观意志，而have to表示由于客观因素不得不做某事。I told her that she must give up smoking. 我叫她必须戒烟。We had to get everything ready that night. 我们那晚得把一切准备就绪。Its getting dark. I have to be off now.3. need和dare need和dare既可用作情态动词，也可用作实义动词。用作情态动词时，主要用于否定句和疑问句。用作实义动词时，可用于各种句式。1) 用作情态动词 need do / neednt do dare do / dare not do dare有过去式dared You neednt telephone him now. 你现在不必打电话给他。I dont think you need worry. 我想你不必发愁。She dare not go out alone at night. 她晚上不敢一个人出去。How dare you say Im unfair? 你竟敢说我不公平？I wonder how he dared say that to the teacher.2) 用作实义动词 need to do / dont(doesnt/didnt) need to do dare to do/ dont(doesnt/didnt) dare (to) do You dont need to do it yourself. 你不必亲自做这件事。We need to tell them the news. 我们需要把这消息告诉他们。We should dare to give our own opinion. 我们要敢于提出自己的观点。He did not dare (to) look up. 他不敢抬头看。3) need 构成一般疑问句时，其肯定回答用must ，否定回答用 neednt 。Need I do it now?Yes, you must. (No, you neednt.)4) need (not) have done表示“本有 （无）必要做某事，然而做了（没有做）”。You neednt have told him about the news. He had known it long before.4.would和used to1）used to表示过去与现在或过去某时与后来的情况有不同，而would只表过去的情况。People used to think that the earth was flat.过去人们认为地球是平的。（现在人们不这么认为。）She would go out for a walk in the morning when she was in the country. 在乡下时，她总是在早晨去散会儿步。（可能现在仍有散步的习惯。）2）used to可表示过去的习惯动作和经常的情况，而would只表示过去的习惯动作。He used to would smoke while writing. 过去他写东西时常抽烟。She used to be fat. 她过去很胖。1. I _ you, because I thought I must be wrong. A. dare not ask B. dare not to ask C. dare not asking D. dare to not ask2. There _ some flowers in the garden. A. were used to be B. used to be C. uses to be D. used to be having3. _ I take it out? Im sorry, you _. A. Could .couldnt B. Might.might not C. Could.can D. May.cant4. You were stupid to climb the tree. You _ hurt yourself. A. may B. might C. will D. might have5. You _ those letters. Why didnt you ? A. should post B. should have posted C. must have posted D. ought to post.6. All the lights are on, the Smiths _ up. A. must get B. is getting C. must be getting D. would get7. He _ lead a horse to the water but he _ not make it drink. A. will.can B. may.can C. may.dares D. dare.can8. Need we do this job now? Yes, _. A. you need B. you should C. you must D. you can9. _ to have lunch with us today? A. Do you likes B. Would you like C. Will you liked D. Have you liked10. He said that you _ watch TV all the evening if you wished. A. may B. must C. can D. might11. -Is John coming by train? -He should, but he _ not. He likes driving his car. A. must B. can C. need D. may12. Peter _ come with us tonight, but he isnt very sure yet. A. must B. can C. may D. will13. Michael _ be a policeman, for hes much too short. A. neednt B. cant C. shouldnt D. wont 14. I thought you _ be hungry, so I have brought you some cakes. A. may B. might C. can D. could15. I wonder how he _ that to the teacher. A. dare to say B. dare saying C. not dare say D. dared say16. Come on! We _ hurry because there isnt much time left. A. may B. must C. can D. need17. Amy did best in the English test. She _hard last week. A. must have working B. should have worked C. should work D. must work18. The fire spread through the hotel very quickly but everyone _ get out. A. had to B. would C. could D. was able to19. -I stayed at a hotel while in New York. -Oh, did you? You _ with Barbara. A. could have stayed B. could stay C. would stay D. must have stayed20. Its nearly seven oclock. Jack _ be here at any moment. A. must B. need C. should D. can