第九讲__情态动词与虚拟语气.doc

第九讲 情态动词与虚拟语气情态动词【考点概况】一情态动词的语法特征1. 情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。2. 情态动词 除ought 和have 外，后面只能接不带to 的不定式。3. 情态动词没有人称、数的变化，即情态动词第三人称单数不加-s。4. 情态动词没有非谓语形式，即没有不定式、分词等形式。情态动词的分类和意义意义情态动词 can, may, might, could, would, will, shall, must, should, ought to, used to二情态动词的基本用法1. can (could)1) 表示能力，could主要指过去时间。例如：I can hear you perfectly well, dont shout into my ears. 别对我大声嚷嚷，我听得见你说话。2) 表示可能（理论上或是逻辑判断上）。例如： He cant (couldnt) finish the project on time. 他不可能准时完成工程。3) 表示允许。例如： Can I open the window? 我可以开窗吗？4) 表惊异、怀疑、不相信等态度。主要用于否定句、疑问句或感叹句中。例如： Where can (could) they have gone to? 他们会去哪儿了呢？5) 比较委婉客气地提出问题或陈述看法。例如： Can (Could) you help me? 帮我一把好吗？.2may (might) 1) 表允许，might可以指过去时间，也可指现在时间，语气更委婉。例如： You may have whatever you like.你喜欢什么就吃什么。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) 表可能（事实上）。可以指过去时间，也可以指现在时间，但语气更加不肯定。例如： He may be not at home. 他可能不在家。3must 1) 表示义务。意为必须（主观意志）。例如： We must act, we must act quickly. 我们必须行动，立即行动2) 表示揣测。意为想必、准是、一定等，只用于肯定句。例如： So be it? For once, must be right! 就这样做？就一次，也许就是对的！4shall 1) 表征询意见，用于第一、第三人称疑问句。例如： Shall I open it?我能打开它吗？2) 表说话人的意愿，有命令、允诺、警告、决心等意思，用于第二、第三人称陈述句。例如：We shall never desert our true friends. 我们决不会抛弃真正的朋友。 （决心）5will 1) 表意愿，用于各种人称陈述句。例如： He will help you if you turn for him. 如果你向他求助他会帮助你的。2) 表请求，用于疑问句。例如： Will you close the window? 请你把窗户关上好吗？3) 表示某种倾向或习惯性动作。例如： Human being will die without oxygen. 人没有氧气就不能活了。6. should1) 表义务。意为应该（某件事宜于做），用于各种人称。例如： You should be polite to your teachers. 你对老师应该有礼貌。2) 表推测，意为想必、一定、照说应该、估计等。例如： 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。3)（表示不确定）万一。例如：If you be interested, Ill tell you the whole story. 万一你有兴趣的话，我可以把整个故事讲给你听。7. would1) 表意愿。例如：: 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。例如： Would you mind cleaning the window? 请把窗户擦一下好吗？3) 表过去反复发生的动作或过去的一种倾向。例如：Every time she was in trouble, she would go to him for help. 她每遇到麻烦都会向他求助。、8.ought to 1) 表义务，意为应该（因责任、义务等该做），口气比should稍重。例如：You are his father. You ought to take care of him.你是他父亲，应当管他。2) 表推测，暗含很大的可能，语气较弱。例如：Han Mei ought to know his telephone number. 9. used to表示过去的习惯动作或状态，现在不复发生或存在。疑问式和否定式有两种。例如： There used to be a building at the street corner, but it has been pulled down. 街道拐角处过去有座楼房，但现在拆了。 I usednt (didnt use) to smoke. 我过去不抽烟。 Used you (Did you use) to go to school on foot? 你过去常步行去学校吗？10.特殊情态动词need和dare的用法：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。例如：You neednt telephone him now. 你现在不必打电话给他。2) 用作实义动词。例如：You dont need to do it yourself. 你不必亲自做这件事。【注意】（I dare say为固定习语） 难点突破1. 情态动词后跟完成时和进行时的用法1) 情态动词+动词完成时情态动词+动词完成时即情态动词+ have + done分词，表示对过去行为或动作进行推测、评论或判断。must have done 表示对过去某事的肯定猜测。其否定或疑问形式都用can(could) 来表示。 例如： Since the road is wet, it must have rained last night.当然对现在发生或将来发生的事情,要用must do 表示猜测, 否定为cant do。例如： He must understand that we mean business.may / might have done表示推测过去某事也许发生了.may 比 might 表示的可能性在说话人看来稍大些。例如：I cant find my keys. I may / might have left them at the school yesterday.could have done 在肯定句型中, 往往用作委婉的批评. 本应该做什么,而没做; 有时也用作猜测。例如：You could have told us earlier.ought to / should have done和 ought not to / shouldnt have done用于对已发生的情况表示责备、不满，分别表示本应该和本不应该。例如：With all the work finished, I should have gone to the party last night.neednt have done 表示过去做了某事，但没有做的必要， 意为本没必要。例如： You neednt have waken me up; I dont have to go to work today.【注意】表示推测过去某动作发生的可能性时，就表示的可能性程度而言，must最大，could其次，may更次之，might最小。例如： I wonder how Tom knew about your past. He must / could / may / might have heard of it from Mary.2) 情态动词+动词进行时情态动词+行为动词进行时（即情态动词+ be + doing形式），表示推测或评论某动作现在是否正在进行。例如： He must be playing basketball in the room. She may be staying at home.3) 情态动词+动词完成进行时情态动词+行为动词完成进行时（即情态动词+ have been + v-ing形式），表示推测或评论过去某动作是否正在进行或一直在进行。例如： They should have been passed the exam.三、几组词的辨异1. can 和be able to1）情态动词can只有两种形式，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 five. 玛丽会弹钢琴。她五岁起就会弹了。2）用在过去时中，could经常表示能够做某事，事实上不一定去做，而was / were able to则表示过去做成了某事。在否定句中两者可通用。He could play ping-pang ball but he dont feel like it now. 他会打乒乓球，但是他今天不想打。2. must和 have to must表示主观意志，而have to表示由于客观因素不得不做某事。must没有过去式，除在间接引语中可用于表示过去时间，在直接引语中表示过去时间应该用had to代替。She must finish her homework. 她必须完成家庭作业。3. would和used to 1）used to表示过去与现在或过去某时与后来的情况有所不同，而would只表示过去的情况。Women used to think they were on the shelf at 30.过去女人一到30岁就认为是过了结婚年龄.（现在人们不这么认为。）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。I used to get up early and take an hours walk before breakfast.我过去常常起床很早并且在早餐前散步一小时。虚拟语气【考点概况】一、语气的定义和种类l、语气：语气是动词的一种形式，它表示说话人对某一行为或事情的看法和态度。2、语气的种类： (1)陈述语气: 表示动作或状态是现实的、确定的或符合事实的，用于陈述句、疑问句和某些感叹句。例如：We are not here. What a delicious cake it is!(2)祈使语气: 表示说话人的建议、请求、邀请、命令等。如: Close the door, please。(3)虚拟语气: 表示动作或状态不高考资源网是客观存在的事实，而是说话人的主观愿望、假设或推测等。例如: If I were you, I should work hard. 二、虚拟语气在条件从句中的用法条件句有两类，一类是真实条件句，一类是虚拟条件句。如果假设的情况是有可能发生的，就是真实条件句。在这种真实条件句中的谓语用陈述语气。例如: If it doesnt rain tomorrow, we will climb up the hill. 如果假设的情况是过去或现在都不存在的，或将来不大可能发生的，则是虚拟条件句。例如: If I had seen her yesterday, I would have told you about it.在含有虚拟条件句的复合句中，主句和从句的谓语都要用虚拟语气。现将虚拟条件从句和主句的动词形式列表如下:从 句主 句与现在事实相反动词的过去式（be的过去式一般用were）would/ should/ could/ might + 动词原形与过去事实相反had + 过去分词 would/ should/ could/ might + have + 过去分词与将来事实相反 动词过去式，should + 动词原形，were to + 动词原形would/ should/ could/ might + 动词原形注: 主句中的should只用于I、we，但在美国英语中，should常被would代替；从句中的should可用于各种人称。l、表示与现在事实相反的假设和结果。例如: If he were here I could explain to him. 2、表示与过去事实相反的假设和结果。例如: If you had prepared in advance, you wouldnt be in such an awkward position.3、表示与将来事实可能相反的假设和结果。例如: If it were fine tomorrow, I would go shopping.4、有时条件从句中的动作和主句中的动作发生的时间不一致（表示错综时间的虚拟语气），这时动词的形式要根据它所表示的时间加以调整。例如: If you had stuck around, you d have seen the fireworks.5、虚拟条件句可以转换成下列形式: (l)省略连词if。在书面语中，如果虚拟条件从句中有were，had 或 should，可以把if省略，把这几个词放到主语之前，构成主谓倒装。例如: Were I you I should wait.(2)用介词短语代替条件状语从句。有时假设的情况并不用条件从句表示出来，而是通过介词短语来表示。例如: But for music (=Were it not for music), life would be dull.Without water (If there were not water), there would be no fish. 在暗含虚拟条件的简单句中，虚拟语气可通过上下文表现出来。谓语动词用should/ would be形式和should/ would have been虚拟形式。例如: What would I have done without you? (条件暗含在分词短语without you中) It would be easier to do it this way. ( 条件暗含在不定式短语to do it this way中) 6、省去条件从句或主句：表示虚拟语气的主句或从句有时可以省略，但其含义仍可以推知。(1)省去条件从句。例如: You could have done your own homework .（省去了If you had wanted to)(事实是:你自己没写家庭作业，因为你不想写。)(2)省去主句(常用以表示愿望)。例如: If my grandmother were with me! (事实是:祖母已不在世。)三、虚拟语气的其他用法l、虚拟语气在主语从句中的用法：在It is important (strange，natural，necessary)that这类句型里，that所引导的主语从句中的谓语动词常用 “should十动词原形”结构，表示某事是重要、奇怪、自然、必要等意义。如: It is necessary that every student (should) work hard.2、虚拟语气在宾语从句中的用法：(1)在动词wish后的宾语从句中，表示与现在或过去的事实相反，或对将来的主观愿望，从句通常省略连词that。1)表示对现在情况的虚拟，从句动词用过去式或过去进行式(be动词一般用were)。例如: I wish I could argue with you.2）表示对过去情况的虚拟，从句动词常用had十过去分词。例如: I wish I hadnt become so conscious of every little nuance. 3)表示对将来的主观愿望，谓语动词形式为would十动词原形。此时要注意，主句的主语与从句的主语不能相同，因为主句的主语所期望从句动作能否实现，取决于从句主语的态度或意愿(非动物名词除外)。例如: I wish it would stop raining.(2)在suggest，demand，order，propose，insist，command，request，desire等动词后的宾语从句中，谓语动词用“should + 动词原形”，表示建议、要求、命令等。例如: I request that he should leave. 3、虚拟语气在状语从句中的用法(1)在带有even if/ even though引导的让步状语从句的主从复合句中，主句和从句都用虚拟语气，动词形式与含有非真实条件句的虚拟语气相同。例如: Even if he had been ill, he would have worked hard. (2)由as if或as though引导的状语从句表示比较或方式时。从句谓语形式为动词的过去式(be用were)或 “had十过去分词”。例如: Dont treat me as if I were a child. 注:如果表示的事情可能会发生，那么方式状语从句中的谓语动词可用陈述语气。(3)在in order that或so that引导的目的状语从句中，谓语动词多用 “could或might（有时也用should）+ 动词原形”。例如: I study hard, so that I may not fail in the examinations. 4、虚拟语气在从句中的用法：在It is time (that) 句型中，定语从句的谓语动词常用虚拟语气表示将来，动词形式一般用过去式，意思是该干某事的时候了。例如: Its (high) time we did housework. 5、虚拟语气在简单句中的用法(1)情态动词的过去式用于现在时态时，表示说话人的谦虚、客气、有礼貌，或委婉的语气，常见于日常会话中。例如It would be better if the school authorities should see to it. (2)在一些习惯表达中。如: I would rather not tell you. (3)用“may + 动词原形”表示祝愿、但愿”，此时may须置于句首（多用于正式文体中）。例如：May you have a fine trip! 旅途愉快！ May you live happily! 生活快乐！1. Isnt that Anns husband over there?No, it be him, Im sure he doesnt wear glasses.A. cantB. must not C. wontD. may not2. You be tiredyouve only been working for an hour.A. must notB. wontC. cantD. may not3. I often see lights in that empty house. Do you think I report it to the police？A. shouldB. shall C. mayD. can4. When a pencil is partly in a glass of water, it looks as if it _.A. breaksB. has broken C. were brokenD. had been broken 5. I didnt see your sister at the meeting. If she _, she would have met my brother.A. has comeB. did come C. cameD. had come6. If he _, he _that food.Luckily he was sent to the hospital immediately. A. was warned; would not take B. had been warned; would not have takenC. would be warned; had not taken D. would have been warned; had not taken7. Mr.White at 8:30 for the meeting, but he didnt show up.A. should arrive B. should be arriving C. should have arrived D. should have had arrived8. Ill tell Mary about her new job tomorrow.You her last week.A. ought to tellB. would have told C. must tellD. should have told9. Lets go and have a good drink tonight. Have you got the first prize in the competition?A. What for?B. Thanks a lot. C. Yes, Id like to.D. Why not?10. English is a language that many people around the world_ not speak perfectly but_ at least understand.A. may; can B. would; might C. will; mustD. could; might11.Didnt they come to the party last week?Yes. They didnt want to come with us at first, but then we _ persuade them.A. wouldB. could C. were able toD. had to12.I promise her daughter _ get a nice present on her birthday. Will it be a big surprise to her?A. shouldB. mustC. wouldD. shall13. All of us had a good time in the picnic last Sunday. Pity you werent there.I really _come but I was looking after my mother in hospital.A. mustB. ought toC. need haveD. should have14. Did you scold him for his carelessness?Yes, but _ it.A. I would rather not do B. Id rather not have done C. I shouldnt do D. Id better not do15. Just as we were sitting down to have dinner, the telephone _ ring.A. mustB. couldC. mightD. need16. Would you like to stay for another two days?Sorry, I _. One of my best friends is coming to see me.A. mustntB. cant C. needntD. wont17. Where is Johnson? I cant find him anywhere.He _ letters upstairs.A. might have written B. must have written C. must be writing D. must write18. Mrs Smith, I will fetch ten chairs for the meeting.You _fetch ten; six will do.A. may not B. mustnt C. needntD. cant19. You _ pay too much attention to your reading skill, as it is so important.A. cantB. shouldC. mustD. neednt20. Can you come to attend our party tonight?Sorry, but I do wish I _.A. hadB. can C. willD. could21. It is necessary that people both young and old in China _some English to be prepared for the Olympic Games to be held in Beijing in 2008.A. learnB. will learnC. must learnD. have learned22. If he his legs in the last training, he the coming World Cup, which he has been longing to compete in.A. hadnt hurt; would join in B. hadnt hurt; would have taken part inC. didnt hurt; would go in for D. didnt hurt; would have taken part in23. I was caught in a traffic jam for over an hour, otherwise I _you waiting for such a long time.A. will not keepB. have not kept C. had not kept D. would not have kept24. Though the girl had been suffering from the blood disease, she acted as if nothing _ to her while facing her friends and relations.A. happenedB. would happenC. was happenedD. had happened25. Its high time that we students _ even harder at our lessons as the national entrance examination is coming nearer.A. workB. will work C. workedD. have to work26. _him not to do so, he wouldnt havemade such a serious mistake.A. Did I persuadeB. If I persuade C. If I should persuadeD. Had I persuade27. His suggestion that you _once more sounds reasonable.A. tryB. tried C. must tryD. can try28. Do you mind if we set out earlier tomorrow morning?Well, Id rather you_.A. dontB. didntC. wont D. wouldnt29. I _ to your birthday party last Sunday. Unfortunately, you were out on business.A. had comeB. came C. would comeD. would h