高中情态动词与虚拟语气详解.doc

戴氏教育 精品堂学校 高三英语春季经典教材 英语教研组 DSE金牌英语专题系列 高三英语春季专题四 情态动词与虚拟语气l 轻松刻一美国教授在上课，有个学生问道:Can I go to the bathroom？教授回答:I dont know. You must know if you can go to the bathroom.这里学生想表达的意思很明显，就是我能去上厕所吗？教授当然也明白他的意思，只是故意逗他玩的Can也有表示人具有某种能力，比如上厕所的能力所以教授说我不知道（你有没有这个能力），你自己应该知道你有没有能力上厕所其实跟人提请求用can不是太礼貌，最好是说Could I或者Would you mind.等等这也是教授跟他开玩笑的原因。l 知识点顾 1.非谓语作状语的区别 2.对不定式和动名词作宾语的考查3.对动词时态和非谓语的考查1. The day we looked forward to _ . A. come B. coming C. has come D. have come2. Whom would you rather _ the work? A. to have to do B. to have do C. have to do D. have do 3. Do you think it any good _ with him again? A. to talk B. talking C. to talking D. having talked4. Sometimes new ideas have to be tested many times before _ . A. accepting fully B. being fully accepted C. fully accepting D. fully being accepted5. The government forbids _ such bad books. A. published B. to publish C. publish D. Publishingl 重点知识解u 词汇“背多分”Do(v.)do a good deed 干得好，搞好工作 do away with 消灭，清除，取消，破除do good 有好处，有用处，做好事 do harm 有害处，不利do one a favour 帮个忙 do one good对某人有好处do ones best 尽力，竭力 do the deed 付诸行动，生效do ones duty 履行职责 do up 收拾，整理，修理，打扮，包，捆，系 do with 处理，需要，想，将就用 do wonders 创造奇迹do wrong(right) 做错（对） have sth (nothing)to do with和有（无）关Keep(v.)keep a promise 遵守诺言 keep a secret 守秘密keep watch 注意，警惕，提防 keep back 扣下，隐瞒，忍住（眼泪）keep body and soul together 维持生活 keep in mind 记住，想着keep off 避开，挡住，不接近 keep ones balance 保持平衡keep on继续（干） keep out 遮挡，使不入内keep silence 保持沉默（安静） keep sb from doing sth阻止某人做某事keep up 保持，维持，继续（某活动） keep up with 不落在后面，跟上，及时了解（情况）All(a.,pron.&n.) all by oneself 独立，单独 above all 首先，特别是，最重要的是after all 到底，毕竟 first of all 首先in all 总共 most of all 最最all at once 突然，同时，马上 all of a sudden 突然all right 好吧，行，情况不错 all sorts of 各种各样的all kinds of 各种各样的 all the best 万事如意all the more 更加 all the same 尽管如此，仍旧（照样）all the year round 一年到头u 语法大观园 考点一 情态动词的基本用法1.can与could的用法（1）表示能力。Can 主要指现在时间，could主要指过去时间。Two eyes can see more than one. 两只眼比一只眼看得清。Could the girl read before she went to school? 这女孩上学前能识字吗？（2）表示客观的可能性（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）表示请示和允许。Can I have a look at your new pen? 我可以看一看你的新钢笔吗？He asked whether he could take the book out of the readingroom. 他问他可不可以把书带出阅览室。（4）表示请示，比较委婉客气地提出问题或陈述看法。口语中常用could代替can，使语气更婉转。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。（5）表示惊异、怀疑、不相信的态度：（主要用于否定、疑问和惊叹句中）不耐烦，难道会，究竟。Where can (could) they have gone to? 他们会去哪儿了呢？He cant (couldnt) be over sixty. 他不可能超过六十岁。How can you be so careless? 你怎么这么粗心？（6）指理论上的可能性，并不涉及是否真的发生。You mustnt smoke while youre walking around in the wood. You could start a fire. 在林子里走时勿吸烟，那样可能会引起火灾。2.may与might的用法 (1)may表示允许、许可。might可以指过去时间，也可指现在时间表语气更委婉。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.否定回答时，一般要用mustnt,表示“禁止，阻止”之意，但也可以用may not/ Please dont . / Youd better not. / No, you mustnt.等，表示“不可以”，以免显得太严峻或不客气。You may take whatever you like. 你喜欢什么就拿什么。He told me that I might smoke in the room. 他告诉我可以在房间里抽烟。May I watch TV after supper?晚饭后我可以看电视吗？Yes, please. /No, you may not(you mustnt). 是的，可以。不，你不能。（2）在表示请示、允许时，might比may更委婉一些。用May I.征询对方许可在文体上比较正式，用Can I.征询对方意见更为常见。Can/May (Might) I ask for a photo of your baby? 我可以要一张你宝宝的照片吗？（3）表示可能性的推测，含有“或许、大概、可能”之意，用might代替may时，则语气显得更加不肯定（不用于疑问句） He may be at home. 他可能在家。She may not know about it. 她可能不知道这件事。He was afraid they might not agree with him. 他担心他们可能不同意他的意见。They might be having a meeting, but Im not sure. 他们有可能在开会，不过我不肯定。（4）may用于祈使句中表示祝愿。 May you succeed! 祝你成功！3. must的用法（1）表示义务。意为“必须”（主观意志）。We must do everything step by step. 我们一切都必须循序渐进地做。You mustnt talk to her like that. 你不许那样对她说话。-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。（这种情况下，一般不用mustnt）（2）表示揣测。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。 4. shall与should的用法（1）shall用于第一、第三人称疑问句中，征求对方的意见和向对方请示。Shall I get you some tea? 我给你点茶好吗？Shall the boy wait outside? 让那男孩在外面等吗？What shall we do this evening? 我们今晚做什么？（2）shall用于第二、第三人称陈述句中，表示说给对方的命令、警告、允诺、决心或威胁。 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）He shall be sorry for it one day, I tell you. 有一天他会后悔的，我告诉你。（警告）Nothing shall stop us from carrying out the plan. 什么也不能阻止我们执行这项计划。（决心）（3）should用于表示劝告和建议，作“应该”讲。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。（4）should用于表示推测，表示某个情况是合理的，正常的，符合逻辑的。The film should be very good as it is starring firstclass 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。（5）should用于第一人称时可表示说话人的一种谦逊、客气、委婉的语气。（6）should表示说话人对某事不能理解，感到意外惊异的意思，意为“竟会”。5.will与would的用法（1）用于表示意志或意愿。will指现在，would指过去。I will do anything for you. 我愿为你做任何事。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。I said I would do anything for you. 我说过我愿意为你做任何事。（2） 表示请示、建议等，用于疑问句。would比用will委婉、客气些。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？Would you like another glass of beer? 再来杯啤酒好吗？Would you mind cleaning the window? 请把窗户擦一下好吗？（3） 表示习惯性动作，译作“总是，惯于”。will指现在，would指过去反复发生的动作或过去的一种倾向。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。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。（4） 表示预料或猜想，表示“大概会”。They wouldnt have anything against it. 他们不会有什么反对意见。（5）用于否定句中，表示“不肯，不乐意”。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。注意：would与used to之区别：would可用来表示过去反复出现的动作，但不能表示过去存在的状态，而used to则着眼于今昔对比。6.need与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） need表示“需要,必要”之意。作情态动词，仅用于否定句和疑问句中，且只有现在时，其他时态用have to的相应形式代替。 -Need I come? -Yes, you must. -我需要来吗？ -需要。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。（2） need若用作实义动词时，其变化与一般动词相同。其后可接“n./to+动词原形/doing”作宾语。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。The table needs painting (to be painted.). 桌子需要油漆一下。（3） dare表示“敢，敢于”之意。作情态动词时，主要用于疑问句、否定句和条件从句，一般不用于肯定句中。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？Not one of them dared mention this. 他们谁也不敢提这件事。（4） dare用作实义动词时，其变化形式与一般动词相同。在肯定句中，dare后面通常接带to的不定式，在否定句和疑问句中,dare后面既可接带to的不定式，也可接不带to的不定式。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。I dare say hell come again. 我想他会再来的。（I dare say为固定习语）7. ought to的用法（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）表示推测，暗含很大的可能，语气较弱。表示某个情况是合理的，符合逻辑的，注意与must表示推测时的区别。 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。8. used to的用法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。He used to live in the countryside, but now he lives in the city.他过去住在乡下，现在住在城里。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，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？百搭的niceNice就是个“百搭”，在各种场合、各种情景下表达“好”的意思。你能用多少词代替nice呢？一起来个brainstorm看看nice到底有哪些意思吧！ Nice=good, pleasant, attractive, enjoyable 形容某个东西、某个气味、某个经历时，nice最言简意赅表达开心、享受。Did you have a nice stay in London? 你在伦敦过的开心吗？(Nice=lovely, pleasant, charming, sweet, adorable)再来发个好人卡，“You are a nice guy but”=你真人真好，只不过姑娘口中的nice，也就是说你可爱、招人喜欢、有魅力、嘴巴甜、招人怜，这么好的你姑娘为什么要打发走呢！You are a nice guy but I prefer man with abs. =你是个好人，但是我喜欢有腹肌的男人。Nice=something you want Nice也能表达意愿，你知道吗？Itd be nice if I could enjoy a spacious room with no distraction from roommates. =如果我能有一间大房间没有室友骚扰就好了。 考点二 情态动词表推测表示推测的情态动词有表示“一定” 的must ，表示“理应”的should， ought to 和表示“可能”的can， could，may， might 。 1 must表示较有把握的推测，常用于肯定句。 具体有三种用法： （1） 对将来情况的推测，用“must 表示动作的动词”。 You must walk miles and miles among the hills without meeting anyone 你一定会在山里一连走好几英里而遇不到一个人。 （2） 对现在或一般的情况的推测，用 “must be”， “must be -ing” 或 “must表示状态的动词”。 You must be hungry after a long walk 你走了那么长的路，一定饿了吧。 Now they must be looking for you他们现在一定正在找你。 He must know the answer to this question 他一定知道这个问题的答案。 （3）对已发生事情的推测 ，用“ must have 过去分词”。 They must have earned a lot of money他们一定挣了很多钱。 They must have gone out again他们准是又出去了。 2 should，ought to表示推测时，意为 “想必会，理应 ” 。 There should （ought to） be some reason for his absence 他缺席想必是有某种原因的。 Its seven oclock Jack should （ought to）be here at any moment 现在七点钟了，杰克理应随时到达。 3 在肯定句中，表示对现在或将来把握不大的推测用“may （ might ）十动词原形”，might比may的可能性更小；表示对过去把握不大的推测用“may （might ） have 过去分词”。 The notice might come tomorrow通知明天可能会来 。 He may be busy these days这些天他可能很忙。 You might have heard of that man你也许听说过那个人。 They may have settled the problem他们可能已经解决了这个问题 。 4 在疑问句中，对现在表示推测用“can （could） 动词原形”，对过去表示推测则用“can（could） have 过去分词”；在否定句中，对现在表示推测用“cant 动词原形”，对过去表示推测则用“cant （couldnt）have 过去分词” 。 What can it be if it is not a knife？如果那不是一把刀子，又会是什么呢？ Could they have put up the notice？他们可能把那张通知贴出去了吗？ It cant be the headmaster He has gone to America 这不可能是校长，他去美国了。 They cant have finished the work so soon他们不可能这么快就完成了工作。 注意：can （ could ） 和 may （ might ） 都可用于否定句，但前者意为“不可能”，语气较强；后者意为“可能不，或许不” ，语气较弱。如： They cant be having a meeting now他们现在不可能在开会。He may not know the scientist。他也许不认识那位科学家。 考点三 情态动词+完成体/ 进行体1.“情态动词+have done”的用法（1）must have done对过去某事的十分肯定猜测He isnt here. He must have missed the train. 他还未到，一定是没赶上火车。（2）may/might have done对过去某事的可能性猜测You may (might) have read about it. 你可能在报上已经读到这件事了。（3）cant/couldnt have done对过去某事的否定猜测He cant have written this letter 这封信不可能是他写的（4）should/ought to have done过去应该做而未做I should have finished the work earlier. 我应当早一点完成这项工作的。（5）shouldnt/oughtnt to have done过去不应该做而实际上做了There was a lot of fun at yesterdays party. You ought to have come, but why didnt you? 昨天的聚会非常有意思。你本应该来，为何不来呢？（6）neednt have done 本没有必要做的事实际却做了He neednt have worried about it. 他本不必为此事担心。（7）can/could have done本来能够做的（有能力做）事实际却未做到You could have been more careful. 你本来可以更细心的。2.情态动词+be doing 情态动词后跟进行式，表示“想必正在”，“可能正在”，“应当正在”等意。Its twelve oclock. They must be having lunch. 现在是十二点。他们一定正在吃饭。They may be discussing this problem. 他们可能正在论讨这个问题。He cant be telling the truth. 他说的不可能是真话。She shouldnt be working like that. Shes still so weak. 她不应当那样干，她身体仍那么虚。 考点四 几个情态动词的特殊用法易错点1. 情态动词的误用(2008辽宁，22) Peter be really difficult at times even though hes a nice person in general. A. shallB. should C. canD. must2. 情态动词+ have done 结构的误用 (2008江西，26) What a pity! Considering his ability and experience, he better.A. need have doneB. must have doneC. can have doneD. might have done3. 条件句中虚拟语气的误用 fired, your health care and other benefits will not be immediately cut off.A. Would you beB. Should you beC. Could you beD. May you be 4. 虚拟语气中省略的易错点Dont you think it necessary that he to Miami but to New York? I agree, but the problem is he has refused to.A. will not be sent; that B. not be sent; thatC. should not be sent; what D. should not send; what 考点五 虚拟语气1.虚拟条件句条件从句主句例句与现在事实相反动词的过去式(be的过去式用were)would/should/could/might+动词原形I dont have a cellphone.If I had one, it would be convenient for me to get in touch with others.与过去事实相反had+ 动词过去分词would/should/could/might+ have动词过去分词If you had come earlier, you would have met him.与将来事实相反动词过去式或should+动词原形或were to+动词原形should/would/could/might+动词原形If it were to rain tomorrow, we would not go out.2. 虚拟条件句的省略虚拟条件句中有were, had, should时, 可把if省略,而把were, had, should放在主语前,用到装结构, 这种结构主要用于书面语中. 如: Were it necessary, I might resign. Had you informed me earlier, I would not have signed the contract. Should I have time, I would call on her. Should it rain tomorrow, we would have to put off the visit to the Summer Palace.3. 错综时间条件句 在这种条件句中,虚拟条件主句和从句的动作发生的时间不一致,因此,主句和从句的谓语动词要根据各自所指的不同时间选择适当的动词形式, 如: If I were you, I would not have missed the film last night. (现在-过去) If they had started in the early morning, they would arrive in half an hour.(过去-将来) If you had asked him when you saw him last time, you would know what to do now. (过去-现在) 4. 含蓄条件句 有些句子中, 没有任何表示虚拟语气的词,短语或从句,但仍要用虚拟语气. 这时,要么是省略了表示虚拟语气的部分, 要么隐含在上下文之中. 如: I would do anything for her (if I could). We would have made a lot of money (but we gave up halfway). Without electricity life would be quite different today. (If there were no electricity). 5.用介词代替条件状语从句, 常见的介词有with , without, but for 如: What would you do with a million dollars (if you had a million dollars?) We would not have finished the word on time without your help (=if you had not helped us) But for the rain, (if it had not been for the rain,) we would have finished the work6.名词性从句中的虚拟语气在虚拟语气问题中，在下列情况下，采用（should）do结构的虚拟语气：（1） 在常用来表示命令、建议、要求、愿望等的词后宾语从句中用虚拟语气，形式为：（should）+动词原形。常这样用的动词有：advise劝告，demand要求，desire渴望，command命令，insist坚持，prefer宁愿，urge主张，order命令，recommend推荐，request要求，require要求，suggest建议。I suggested that we should go there on foot.注意 suggest, insist等动词不表示建议、要求等解释时，其宾语从句中的谓语动词不需要用虚拟语气形式。当suggest表示暗示,表明时,不用虚拟语气,用陈述语气.如: The smile on her face suggested that she was satisfied with our work. Are you suggesting that I am not suited for the job?你是在暗示说我不适合那份工作吗？当insist表示坚持认为之意时, 不用虚拟语气,用陈述语气. 如: The man insisted that he had never stolen the money.（2） 在常用来表示命令、建议、要求、愿望等的词引导的同位语从句中，用虚拟语气。常见的词有：advice, idea, order, plan, demand, proposal, suggestion, request等名词之后的表语从句和同位语从句中.如: My suggestion is that we should hold a meeting this evening （3）wish后宾语从句的虚拟语气，表示没有把握或不太可能实现的愿望 表示对现在情况的虚拟：wish+主语+动词一般过去式或were 表示对过去情况的虚拟：wish+主语+had+过去分词 表示对将来情况的虚拟：wish+主语+would/could/might +动词原形,后的从句不能用should. I wish she were here. I wish you would go with us tomorrow I wish she had taken my advice（4）在“ It is ordered/desired/decided/requested/strange/important/natural/a pity +that从句”等后的主语从句中，从句中的谓语动词部分也要用（should）do形式的虚拟语气结构。此时,it作形式主语，that从句为真正的主语。另外，当suggest“表明，暗示”和insist“坚持说”后接从句时，从句不用（should）do结构，而要用陈述语气。It is desired that we should get everything ready tonight.（5） as if /as though 后有时用虚拟语气 1) 从句所设想的时间与主句动作同时发生,从句动词用过去时(be用were) It looks as if she were sick. He looks as though he knew the girl. 2) 从句所设想的时间动作于主句谓语发生,从句动词用had+过去分词. 如: I feel as if we had known each other for years. He talks about pyramids as though he had seen them himself. 7. would rather, had better后的句子的虚拟语气 1) 接动词原形, 指现在或将来的时间, 表示主语的主观愿望和选择 I would rather do it today. You had better not go dancing tonight. 2) 接不定式的完成式, 表示过去的某种不恰当的选择. 如: I would rather not have told her the news. She is such a gossip 3) 接从句, 用一般过去时, 表示现在或将来的愿望;用过去完成时,表示过去的愿望.如: I would rather you paid the money yourself. I would rather she had not done that. 8. it is (high) time that .句型中, 从句的谓语动词用过去式,或should +动词原形, 其中should不能省掉.如: It is time that you went to school. It is time that we should start out. 9. 在含有if it were not for 或if it had not been for 条件句的虚拟语气中. 如: If it were not for the rain, the crops would die. If it had not been for your help, we could not have finished the work ahead of time. 10. 用于if only引导的感叹句中 If only I were a flying bird! If only I had seen the film!u “辨”地开花 1. can 和be able to1）情态动词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. 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waswere able to则表示“过去做成了某事”。在否定句中两者可通用。He could swim across the English Channel. But he didnt feel like it that day. 他能游过英吉利海峡，但那天他不想游。Yesterday I was able to get home before the heavy rain. 昨天我在下大雨前赶到了家里。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表示“必须，应该”之意，语气比should, ought to强。其否定形式mustnt表示“不准，不应该，禁止”等意。在回答带有must的问句时，否定回答常用neednt或dont have to，表示“不必”，而不用mustnt。表示有把握的推测，意为“一定，准是，想必”，只用于肯定句中。must表示的是说话人的主观看法，而have to则往往强调客观需要。must只有一种形式，而have to则涉及人称、时态等方面的变化形式。两者的否定意义不同，mustnt表示“禁止，不许”，dont have to表示“不必”。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。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。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不同，而would只表过去的情况。People used to think that the earth was flat.