1、解密08 情态动词和虚拟语气备战高考英语之高频考点解密解析版考点详解【考纲解读】 1. 考生应掌握can, could, may, might, must, will, would, shall, should, ought to, need, dare, be able to, used to等情态动词的基本用法。 2. 考生应掌握虚拟语气在非真实条件句、名词性从句及其他句型中的运用。【命题趋势】 情态动词和虚拟语气为中学英语考纲要求的内容，并且是高考内容中的难点之一。预计在以后的高考中，可能会对情态动词和虚拟语气进行考查，且还可能通过虚拟语气形式考查某种时态的某个形式。考向1 情态动词一、
2、 can, could 与 be able to 1. 表示能力（体力、知识、技能）。 Can you lift this heavy box?（体力） Mary can speak three languages.（知识） Can you skate?（技能） 此时可用be able to代替。 can只有一般现在时和一般过去式；而be able to则有更多的时态。 Ill not be able to come this afternoon. 当表示“经过努力才得以做成功某事”时应用be able to，不能用can。如： He was able to go to the party y
3、esterday evening in spite of the heavy rain. 2. 表示请求和允许。 Can I go now? Yes, you can. / No, you cant. 此时可与may互换。 在疑问句中还可用could, might代替，不是过去式，只是语气更委婉，不能用于肯定句和答语中。 Could I come to see you tomorrow? Yes, you can. ( No, Im afraid not. ) 3. 表示客观可能性（客观原因形成的能力）。 Theyve changed the timetable, so we can go b
4、y bus instead. This hall can hold 500 people at least. 4. 表示推测（惊讶、怀疑、不相信的态度），用于疑问句、否定句和感叹句中。 Can this be true? This cant be done by him. How can this be true? 1. (2018北京卷单项填空) In todays information age, the loss of data _ cause serious problems for a company.A. need B. should C. can D. must【参考答案】C 2
5、. (2017北京卷单项填空)Samuel, the tallest boy in our class, _ easily reach the books on the top shelf.A. must B. should C. can D. need【参考答案】C【答案解析】考查情态动词。can表示能力，意为“能够”。故答案为C。句意：塞缪尔我们班个子最高的男孩能够轻松地够到架子顶层上的书。学！科网二、 may, might 1. 表示请求和允许。 might比 may语气更委婉，而不是过去式。否定回答时可用cant 或mustnt，表示“不可以，禁止”。 Might/ May I smo
6、ke in this room? No, you mustnt. May/Might I take this book out of the room? Yes, you can. (No, you cant / mustnt. ) 用May I.？征徇对方许可时比较正式和客气，而用Can I.？在口语中更常见。 2. 用于祈使句，表示祝愿。 May you succeed! might为may的过去式，但也可以代替may，语气较为婉转客气或更加不肯定。He might not come today. 今天他也许不来了。(语气不肯定) You might also get a headache
7、 when you work too hard. 当你工作太努力时，你也可能患头痛。You feel all the training a waste of time, but Im a hundred percent sure later youll be grateful you did it. A. should B. need C. shall D. may【参考答案】D三、 must, have to 1. 表示必须、必要 You must come in time. 在回答引出的问句时，如果是否定的，不能用mustnt（禁止，不准），而用neednt, dont have to（不
8、必）。 Must we hand in our exercise books today? Yes, you must. /No, you dont have to / you neednt. 2. must是说话人的主观看法，而have to则强调客观需要。 must只有一般现在时， have to 有更多的时态形式。 I really must go now. I had to work when I was your age. 3. must表示推测、可能性（只用于肯定的陈述句） Youre Toms good friend, so you must know what he likes
9、 best. Your mother must be waiting for you now.must开头的疑问句，其否定回答通常用dont have to或neednt。而不用mustnt。 Must I finish my homework first? 我必须先完成作业吗？No, you dont have to/ neednt. 不，你不必。can和must在表推测时，can一般用于否定句中，而must 常用于肯定句中。It can not be Li Lei. 那个人不可能是李磊。 It must be Li Lei. 那个人肯定是李磊。1.Cant you stay a littl
10、e longer? Its getting late. I really _go now, My daughter is home alone. A .may B .can C . must D .dare 【参考答案】C【答案解析】句意：你不能再多待会儿吗?很晚了，我必须得走了。我女儿一个人在家。A. may可能，可以，也许； can能，会；C. must必须，必然要，必定会；D. dare敢，胆敢。结合句意，故选C。2. You _be careful with the camera. It costs! A .must B. may C. can D. will【参考答案】A四、 dar
11、e, need 1. dare作情态动词用时, 常用于疑问句、否定句和条件从句中, 过去式形式为dared。 How dare you say Im unfair? He darent speak English before such a crowd, dare he? If we dared not go there that day，we couldnt get the beautiful flowers. 2. need 作情态动词用时, 常用于疑问句、否定句。在肯定句中一般用must, have to, ought to, should代替。 You neednt come so e
12、arly. Need I finish the work today? Yes, you must. / No, you neednt. 注意： dare和 need作实义动词用时，有人称、时态和数的变化。在肯定句 中，dare后面常接带to的不定式。在疑问句和否定句中，dare后面可 接带to或不带to的不定式。而need后面只能接带to的不定式。 I dare to swim across this river. He doesnt dare (to) answer. He needs to finish his homework today.五、 shall, should 1. sha
13、ll 用于第一人称，征求对方的意见。 What shall we do this evening? 2. shall 用于第二、三人称，表示说话人给对方的命令、警告、允诺或威胁。 You shall fail if you dont work hard.(警告) He shall have the book when I finish it.(允诺) He shall be punished.(威胁) 3should表示义务、职责等，意为应该。 You should be strict with yourself as an officer. 作为一名官员，你应该严格要求自己。六、 will,
14、 would 1. 表示请求、建议等，would更委婉。 Will / Would you pass me the ball, please? 2. 表示意志、愿望和决心。 I will never do that again. They asked him if he would go abroad. 3. would表示过去反复发生的动作或某种倾向。would表示过去习惯时比used to正式，且没有“现已无此习 惯”的含义。 During the vacation, he would visit me every other day. The wound would not heal.
15、(2018新课标II卷短文改错) As kid, I loved to watch cartoons, but no matter how many times I asked to them, my parents would not to let me.【参考答案】删除let前的to【答案解析】would后跟动词原形，故把to删除。七、 should, ought to 1. should, ought to表示“应该”，ought to表示义务或责任，比should语气重。 I should help her because she is in trouble. You ought to
16、 take care of the baby. 2. 表示劝告、建议和命令。should, ought to可通用，但在疑问句中常用should。 You should / ought to go to class right away. Should I open the window? 3. 表示推测 should , ought to (客观推测), must(主观推测)。 He must be home by now. (断定他已到家) He ought to/should be home by now.(不太肯定) This is where the oil must be.(直爽)
17、 This is where the oil ought to/should be.(含蓄)考向2 情态动词+have done情态动词have done用法must have done一定做过某事，其否定形式为cant/couldnt have donecan/could have done(1)本来能够做但却未做(2)可能做过某事cant/couldnt have done不可能做过某事may/might have done或许/可能做过某事should/ought to have done本该做但却未做，其否定形式表示本不该做但却做了neednt have done做了本没有必要做的事情
18、1.must have done表示对过去事情的肯定推测，译成一定做过某事，该结构只用于肯定句。 It must have rained last night, for the ground is wet. 昨晚一定下雨了，因为地面还是湿的。You must have been mad to speak to the servant. 你和仆人说话，一定是发疯了。2.cant have done表示对过去事情的否定推测，译成不可能做过某事。Mr Smith cant have gone to Beijing, for I saw him in the library just now. 史密斯
19、先生不可能去北京了，我刚才还在图书馆见过他。Mary cant have stolen your money. She has gone home. 玛丽不可能偷你的钱，她回家去了。3.can have done表示对过去行为的怀疑，用于疑问句，译成可能做过吗？。There is no light in the room. Can they have gone out? 屋里没有灯，他们可能出去了吗？There is nowhere to find them. Where can they have gone? 到处找不到他们，他们可能到什么地方去呢？4.could have done是虚拟语
20、气，表示对过去事情的假设，意思是本来能够做某事而没有做。He could have passed the exam, but he was too careless. 本来他能够通过考试，但是他太粗心。5.may have done表示对发生过的事情的推测，意思是可能已经或也许已经，用于肯定句中。 What has happened to George? 乔治发生了什么事？I dont know. He may have got lost. 我不知道，他可能迷路了。6.might have done表示对过去事情的推测，might与may意思相同，但可能性更小。多用于虚拟语气结构中。 She
21、might have achieved greater progress, if you had given her more chances. 如果你多给她点机会，她可能已经取得了更大的成绩。学！科网7.would have done虚拟语气，表示对过去事情的假设，意思是本来会。I would have told you all about the boys story, but you didnt ask me. 我本来会告诉你这个小男孩的故事，但是你没有问我。8.should have done意思是本来应该做某事，而实际没做。shouldnt+have+done表示本来不应该做某事，而
22、实际做了。含有指责对方或自责的含义。Tom, you are too lazy. The work should have been finished yesterday. 汤姆，你太懒惰了，这项工作本来应该昨天就做完的。Look, Tom is crying. I shouldnt have been so harsh on him. 看，汤姆哭了，我本不应该对他如此严厉的。9.ought to have done表示过去应该做而实际并没有做，译成理应做，往往表示遗憾。与should have done用法基本一样。 I ought to have gone home last Sunday
23、. 我理应上星期日回家。You ought not to have given him more help. 你不应该帮助他那么多。10.need have done表示本来需要做某事而实际没有做。neednt have done则表示本来不需要做某事而实际做了I neednt have bought so much wine only five people came. 我本来没有必要买这么多酒，只来了五个人。He need have hurried to the station. In that case, he wouldnt have missed the train. 他本来需要快点
24、去车站的，那样的话，他就不会误了火车。 Sorry, Mum! I failed the job interview again.Oh, its too bad. You _ have made full preparations.A. must B. can C. would D. should【参考答案】D难点剖析情态动词表猜测的用法：一、can / could用于表推测的用法(1) 从使用句型上看，can 通常只用于否定句或疑问句，一般不用于肯定句，而could 可用于肯定句、否定 句和疑问句。两者没有时间上的差别，只是could 比 can 更委婉，更不确定。如： It cant co
25、uldnt be true. 那不可能是真的。 What can could they be doing? 他们会在干什么呢? We could go there this summer. 今年夏天我们可能要去那儿。注：can 有时也用于肯定句中表示推测，主要用于表示理论上的可能性(即从理论上看是可能的，但实际未必会发生)，或表示“有时”之意。如： Even experienced teachers can make mistakes. 即使是有经验的教师也可能出错。 She can be very unpleasant. 她有时很令人讨厌。(2) 从时间关系看，对现在或将来情况作推测，后接动
26、词原形；对正在进行的情况作推测，后接 be doing 结 构；对过去情况作推测，后接动词完成式。如： He could have gone home. 他可能已经回家了。 He cant couldnt have understood. 他不可能理解了。 Why does he know this? Can Could someone have told him about it? 他怎么知道? 会是哪个人告诉他了吗?(3) “could+完成式”除表示对过去的推测外，还有以下重要用法： 表示过去没有实现的可能性，常译为“本来可以”。如： I could have lent you the
27、moneyWhy didnt you ask me? 我本来可以借这笔钱给你的。你为什么不向我提出? 用来委婉地责备某人过去应该做某事而没有去做，常译为“本来应该”。如： You could have helped him. 你本来应该帮助他的。 表示“差点儿就要”。如： I could have died laughing. 我差点儿笑死了。二、 may / might用于表推测的用法 表示推测，两者都可用，只是 might 比 may 语气更不确定，表示的可能性更小。(1) 在句型使用方面：两者均可用于肯定句和否定句，但用于疑问句时，may通常不用于句首，但可用于疑问句的句中（如特殊疑问句
28、等），而might尽管可以用于疑问句的句首，但不算普通，通常会改用其他句式（如用could等）。如： He may might know the answer. 他可能知道答案。 He may might not believe you. 他可能不会相信你。 And who may might she be? 那么她会是哪一位呢？(2) 从时间关系看，对现在或将来情况作推测，后接动词原形；对正在进行的情况作推测，后接 be doing 结 构；对过去情况作推测，后接动词完成式。如： He may might tell his wife. 他也许会告诉他妻子。 He may might be w
29、riting a letter. 他可能在写信。 She may might have read it in the papers. 她可能在报上已读到过此事。(3)“might+完成式”除表示对过去的推测外，还有以下重要用法： 表示过去某事可能发生而实际上却并没发生。如： It was really very dangerous. I might have killed myself. 那真的是太危险了，我差点没命了。 A lot of men died who might have been saved很多人本来可以获救的却死了。 表示委婉的批评或责备。如： You might have made greater progress. 你的进步本来可更大一些的。 You might at least have answered my letter. 你至少可以回我一封信嘛。三、must表示推测的用法 must 表示很有把握的推测，其意为“一定会”“肯定会”，只用于肯定句，一般不用于否定句或疑问句。表示对现在或未来的情况作推测，后接动词原形；表示对过去情况的推测，接动词完成式。如： I must be the happiest woman on earth! 我一定是世界上最
