1、1高考语法专题复习之六第六讲 情态动词与虚拟语气【知识梳理】高考常考考点：1. 情态动词本身所表达的意义，如表示禁止、命令、威胁、许诺等意义；may, might, need, should 等的用法。2. “情态动词+have done”表示推测。3. 情态动词后面省略形式的用法区别，如：could (do） ，could have (done) 的区别。4. 虚拟语气中的含蓄条件句以及宾语从句。5. 判断陈述语气与虚拟语气。一、情态动词(一) 情态动词的基本用法1. can be able to couldcan 和 be able to 都表示能力，意思上没多大区别。但 can 只有现在
2、和过去时，而be able to 则有更多的形式。但当成功地完成某一具体动作时，通常不用 could 而用was/were able to 来表示。这时 was/were able to 相当于 managed to，表示经过一番努力，终于能够完成某事。如：The wounded man still was able to get to the village and was saved in the end.can 和 could: can 和 could 都可以表示能力、技能、许可、建议或请求和可能性。但比较委婉客气地提出问题或陈述看法，一般用 could，回答时则用 can。如：Coul
3、d you help me carry the bag?Can I help you?2. may/mightmay/might 表示可能，但 may 比 might 可能性大。如：Why isnt he in class?He may be sick.(生病的可能性较大 )He might be sick.(生病的可能性较小)may/might 表示“ 允许“，may 用于现在时或将来时，might 常用在间接引语中表过去时，但 might 也可用于现在时间，表示比较委婉的语气，回答用 may。如：He says we may leave.He said we might leave.may
4、 / might 表示建议或请求，但 might比 may 更客气，意思更肯定而无过去时态的含义。如：-May / Might I use your bike? -Yes, you can / may. /-No, you mustnt3. must have tomust 表示必须，应该，强调主观意愿，没有时态变化。must 表示肯定的推测。如：The light is still on, so he must be at home.mustnt 表示禁止做某事。如：have to 表示“ 必须、不得不 “，是由于某种外界（客观）原因而“必须 “，“不得不“做某事，也可表示经常的或习惯性的事
5、“必须“做。have to 的否定形式表示不必。have to可用于多种时态中。如：You will have to clean your own boots when you join the army.I have to be at my office every evening.4. should / ought toshould 和 ought to 表示应当、应该，前者比后者语气轻。如：You should / ought to work hard.Since she is not here, he should / ought to be in the classroom.shou
6、ld/ought to 的否定形式表示禁止之意。如：Children shouldnt smoke.should 可表示陈述意见，推出建议或请求；而 ought to 可以表示劝告之意。如：You ought to respect your parents.He suggested that they should leave at once.5. will / would2will 用于各种人称表示“ 意志“、“ 意愿“或“决心“ 等，否定式 wont + 动词。如：I will tell you all about it./ Tom wont do such a thing.will 用于
7、疑问句中，常用在第二称时表示说话人向对方提出“请求“ 或 “询问“如：Will you tell her the news when you see her?will 表示习惯性的动作，有“总是“ 、“惯于“ 的含义。如：Fish will die out of water.would 表示客气的请求、建议或意愿。如：Would you please be quiet?Would you like coffee?would 表示过去反复发生的动作。如：When I passed my school，I would see my teachers who taught me 5 years ag
8、o.6. need: 作“ 必要“讲，既可作情态动词，也可作实义动词。作实义动词时后面的动词不定式要带 to，其变化与一般动词相同。如：I need to think it over.Need you go now? Yes, I must./No, I neednt 7. dare: 表示“敢“ 的意思。作为情态动词时，主要用在疑问句和否定句中。dare 若作实义动词，后面可带 to 的不定式，此时 to 也可以省略。dare 与 need 的用法相似。如：How dare you say that?She doesnt date(to)ask her father.8. used to:
9、表示过去常常发生的动作或存在的习惯，但现在已不复存在了。如：He used to smoke.9. shallshall 作为情态动词用于第二、三人称，表示说话人的意愿，有“命令 “、“警告、威胁、强制“和“允许“等意思。如：We/You shall do as our teacher says.在疑问句中，shall 用于征求对方的意见或请求指示，常用于第一、第三人称。如：Shall he go out for a walk?二、虚拟语气：用于条件状语从句中1. 表示与现在事实相反的假设条件状语从句中的谓语动词：“过去式（be 动词的过去式用 were）“ ，主句中的谓语动词:“would/
10、should/could/ might + 动词原形 “。如：If I were a boy, I would join the army.If she had time, she should go with you.2 表示与过去的事实相反条件状语从句中的谓语动词：过去完成时，主句中的谓语动词：“would/should/ might / could + have +过去分词“ 。如：If he had taken my advice, he would have succeeded in the competition.3 表示与将来事实相反条件状语从句中的谓语动词：一般过去时或 sho
11、uld(were to) + 动词原形，主句中的谓语动词则用 would / should/could might + 动词原形。如；If it were to rain tomorrow, the football match would be put off.4 错综条件句：当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间作相应调整。如：If they had worked hard, they would be very tired.(从句说的是过去，主句指的是现在)5. 虚拟语气的省略：有时可省略 if,句子则变成下列形式：Were / Ha
12、d / Should +主语+“。如：Were I a boy, I would join the army.3Had he taken my advice, he would have succeeded.Were it not for the expense, I would go to Britain.【疑难点拨】一、 情态动词表示推测或判断的用法1. 表肯定推测：1）对现在和未来的推测：must /may / might /could/should+动词原形2）对过去的推测must /may / might /could/should +have done2表否定推测：1）对现在和未来
13、的推测：cant +动词原形2）对过去的推测cant +have donecant 只用于否定句、疑问名（could 可用于肯定句。例如：It must have rained last night.She may not be at home. = It is possible that she is not at home.She cant be at home. = It is impossible that she is at home.They should be there right now.二、 情态动词在虚拟语气中的用法情态动词用于虚拟语气中表示责备的感情色彩，用法如下：1.
14、 should have done 表示“本来应该做某事而实际上未做“，而 shouldnt have done 则表示“本不应该做某事而实际上做了“ 。如：You should have told me about it earlier.You shouldnt have said such words to your parents.2. ought to have done 也表示“本应该.“，而 ought not to have done 则意为“本不应该.“。如：You ought to have told me about it earlier.You ought not to
15、have said such words to your parents.3. neednt have done 表示“本不必做某事而实际做了“。如：You neednt have walked so quickly since time was enough.4. could have done 表示“本来能 而事实上未做到“。如：I could have come on time, but my car broke on the way.三、虚拟语气用于名词性从句1. 虚拟语气在宾语从句中的运用。“wish + 宾语从句“表示不能实现的愿望，译为“要是就好了 “等。表示现在不能实现的愿望，
16、从句中的谓语动词用一般过去时；表示将来不能实现的愿望，从句中的谓语动词用“would/could + 动词原形“；表示过去不能实现的愿望，从句中的谓语动词用“had + 过去分词“或“could(should) + have + 过去分词“ 。如：I wish it were spring all the year round.I wish I had known the answer.I wish I could fly like a bird.在表示建议、要求、命令等的动词suggest，advise，propose，demand，require，insist，request ，comma
17、nd，order 等后的宾语从句中，谓语动词用 should + 动词原形或是动词原形。如：She suggested we (should) leave here at once.The doctor ordered she should be operated on.2. 虚拟语气在同位语从句和表语从句中的运用。作表示建议、要求、命令等的名词advise， idea，order ，demand ，plan，propo4sal，suggestion，request 等的表语从句和同位语从句，从句中的谓语动词用“（ should） + 动词原形“。如：His suggestion that w
18、e (should) go to Shanghai is wonderful.My idea is that they (should) pay 100 dollars.3. 虚拟语气在主语从句中的运用。在主语从句中，谓语动词的虚拟语气用“should + 动词原形 “的结构，表示惊奇、不相信、理应如此等。如：It is necessary(important, natural, strange, etc.)that we should clean the room every day.It was a pity (a shame, no wonder, etc.)that you shoul
19、d be so careless.It will be desired(suggested, decided, ordered, requested, proposed, etc.)that she should finish her homework this afternoon.注意：这种从句表示的是事实。如果说人对这种事实表现出惊奇的情感，就可用虚拟语气。反之，如果不表示惊奇等情感，that 从句也可用陈述句语气。如：It is a pity that you cant swim.四、虚拟语气在其他场合的运用1 虚拟语气在 as if/as though、even if/even tho
20、ugh 等引导的表语从句或状语从句中，如果从句表示的动作发生在过去，用过去完成时；指现在状况，则用一般过去时；指将来状况则用过去将来时。如：He did it as if he had been an expert.Even if she were here, she could not solve the problem.2 虚拟语气用于定语从句中。这种从句常用于句型“It is (high)time (that) . “中，定语从句的谓语动词用一般过去时(be 用 were)或 should + 动词原形，意思是“(现在) 该“ 。如：Its time that I picked up m
21、y daughter.Its high time we were going.3 虚拟语气用在 if only 引导的感叹句中。如：If only I were a bird./If only I had taken his advice.4 虚拟语气在一些简单句中的运用。情态动词的过去式用于现在时态时，表示说话人谦虚、客气、有礼貌或语气委婉，常出现在日常会话中。如：It would be better for you not to stay up too late.Would you be kind enough to close the door?用于一些习惯表达法中。如：Would yo
22、u like a cup of tea?I would rather not tell you. 5. without, but, but for, otherwise 引起的短语或句子常暗含着含蓄条件。Without you, I would never know him. But for your cooperation, we wouldnt have done the work so well. = If it were not for your cooperation, we we wouldnt have done the work so well.注： without / but
23、 for = If it werent not for/ If it hadnt been for , sb I would be most glad to help you, but I am busy now.I am busy now, otherwise I would do you the favor! 【思维拓展】 1. （2007，湖南， 24）The biggest problem for most plants, which _ just get up and run away when threatened, is that animals like to eat them
24、.Ashant Bcant Cneednt Dmustnt答 案 B解 析 句 意 ： 对 大 多 数 受 到 威 胁 时 又 不 能起 身 逃 跑 的 植 物 来 说 ， 最 大 的 问 题 是 动 物5喜 欢 吃 他 们 。 A shant 将不； B cant 不能C、D 项不合题义。故选 B。点拨 考 生 应 掌握情态动词的基本用法并根据上下文作出选择。变式 You get up and run away when asked to stop by police, or you will be shot at.Ashant Bcant Cneednt Dmustntshant 不允许/
25、必须不（表说话人的意愿） ；mustnt 一定不能/禁止（表主语的意愿） 。故选 A。2. （ 2007，福建， 27）If it were not for the fact that she _ sing, I would invite her to the party.A. couldnt B. shouldntC. cant D. might not 答 案 C解 析 句 意 ： 如 果 不 是 她 真 不 会 唱 歌 ， 我会 邀 请 她 去 参 加 晚 会 。 that 引 导 的 同 位 语 从句 说 明 fact 的 内 容 ， 用 陈 述 语 气 。 故选 C。点拨 考 生 应
26、 能辨别陈述语气与虚拟语气。变式 If she _ sing, I would invite her to the party.A. could B. should C. can D. might 根 据 句 意 ， if 从 句 为 与 现 在 事 实 相 反 的虚拟条 件 句 。 故选 A。3. I was really worried about her. She _home without saying a word.A.mustnt have left B.shouldnt have leftC.couldnt have left D.neednt have left答 案 B 解
27、析 本题考查的是情态动词在虚拟语气中的用法。题目给出的条件是“我确实非常担心你“，因此后面可知应是责备 you 不应该没说一句话就离开了。点拨 考 生 应 掌握情态动词在虚拟语气中的用法。变式 I was really worried about her. She _ me when she left home.A.must have told B.should have toldC.could have told D.need to have told根 据 句 意 可 知 ： 她 应 该 告 诉 我 （ 实 际 没告 诉 我 ） ， 用 虚拟语 气 。 故选 B。4. Are you co
28、ming to my party?Im not sure. I _ go to the cenema instead.A. must B.would C.should D.might答 案 D 解 析 由题目中“Im not sure“,表明我可能去 Jeffs party，也可能去音乐会，故用might。点拨 考 生 应 掌握情态动词的基本用法。变式 The outbreak of bird flu tells us that a sound public health system be built up and strengthened in our country.A. must B.
29、may C.should D.might根 据 句 意 选 should(应该)。故选 C。5. Will you stay for dinner?Sorry, _. My mother is coming to see me.A.I mustnt B.I cantC.I neednt D.I wont答 案 B 解 析 用 will 来向第二人称提问的疑问结构，是表示一种请求和意愿，是用疑问的形式来表达较为婉转的祈使语气，意思是“请你，好吗“，对于这种问句的肯定回答是：Sure! Gertainly! Yes, of course. Id be glad to 等；否定回答通常是：Im so
30、rry, I cant. No, Im afraid I cant. Im sorry, but . Id like to, but .等。点拨 考 生 应 掌握用情态动词表示请求的英语口语，注意情态动词表客气的用法及其在一般疑问句中的问与答。变式 -Must I stay for dinner?6-No, you _. If you have finish your work, you may leave now.A. mustnt B. cantC. neednt D. wontMust?的否定回答用 No,neednt。故选 C。【小题训练】1. Isnt that Anns husba
31、nd over there?No, it be him, Im sure he doesnt wear glasses.A. cant B. must notC. wont D. may not2. You be tiredyouve only been working for an hour.A. must not B. wont C. cant D. may not3. I often see lights in that empty house. Do you think I report it to the police？A. should B. shallC. may D. can4
32、. When a pencil is partly in a glass of water, it looks as if it _.A. breaks B. has brokenC. were broken D. had been broken 5. I didnt see your sister at the meeting. If she _, she would have met my brother.A. has come B. did comeC. came D. had come6. If he _, he _that food.Luckily he was sent to th
33、e hospital immediately. A. was warned; would not takeB. had been warned; would not have takenC. would be warned; had not takenD. would have been warned; had not taken7. Mr.White at 8:30 for the meeting, but he didnt show up.A. should arriveB. should be arrivingC. should have arrivedD. should have ha
34、d arrived8. Ill tell Mary about her new job tomorrow.You her last week.A. ought to tell B. would have told C. must tell D. 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. Englis
35、h is a language that many people around the world_ not speak perfectly but_ at least understand.A. may; can B. would; might C. will; must D. 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. would B. could C. were able
36、 to D. had to12.I promise her daughter _ get a nice present on her birthday.Will it be a big surprise to her?A. should B. mustC. would D. 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. must B. ought
37、toC. need have D. should have14. Did you scold him for his carelessness?Yes, but _ it.A. I would rather not doB. Id rather not have done C. I shouldnt doD. Id better not do715. Just as we were sitting down to have dinner, the telephone _ ring.A. must B. could C. might D. need16. Would you like to st
38、ay for another two days?Sorry, I _. One of my best friends is coming to see me.A. mustnt B. cantC. neednt D. 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
39、the meeting.You _fetch ten; six will do.A. may not B. mustnt C. neednt D. cant19. You _ pay too much attention to your reading skill, as it is so important.A. cant B. shouldC. must D. neednt20. Can you come to attend our party tonight?Sorry, but I do wish I _.A. had B. canC. will D. could21. It is n
40、ecessary 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. learn B. will learnC. must learn D. 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
41、; would join inB. hadnt hurt; would have taken part inC. didnt hurt; would go in forD. 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 keptC. had not keptD. would not have kept24. Though
42、 the girl had been suffering from the blood disease, she acted as if nothing _ to her while facing her friends and relations.A. happened B. would happenC. was happened D. had happened25. Its high time that we students _ even harder at our lessons as the national entrance examination is coming nearer
43、.A. work B. will workC. worked D. have to work26. _him not to do so, he wouldnt havemade such a serious mistake.A. Did I persuade B. If I persuadeC. If I should persuadeD. Had I persuade27. His suggestion that you _once more sounds reasonable.A. try B. triedC. must try D. can try28. Do you mind if w
44、e set out earlier tomorrow morning?Well, Id rather you_.A. dont B. didntC. wont D. wouldnt29. I _ to your birthday party last Sunday. 8Unfortunately, you were out on business.A. had come B. came C. would come D. would have come30. Is John coming by train?He should，but he _ not.He likes driving his c
45、ar.A.must B.can C.need D.may31.The room is so dirty. _ we clean it?Of course.A.Will B.Shall C.Would D.Do32. My English-Chinese dictionary has disappeared. Who _ have taken it? A.should B.must C.could D.would33. I heard they went skiing in the mountains last winter.It _ true because there was little
46、snow there.A. may not be B. wont be C. couldnt be D. mustnt be34. It has been announced that candidates _ remain in their seats until all the papers have been collected.A. can B. will C. may D. shall35. Did the train arrive in time?No.It _two hours ago.A.must have arrive B.ought to have arrivedC.mus
47、t arrive D.ought to arrive36. Look at the trouble I am in! If only I _ your advice.A. followed B. would followC. had followed D. should follow37. It is hard for me to imagine what I would be doing today if I _ in love，at the age of seven，with the Melinda Cox Library in my hometown.A. wouldnt have fa
48、llen B. had not fallenC. should fall D. were to fall38. She insisted that she _ ill of him behind him，but he didnt believe it.A. hadnt spokenB. shouldnt speakC. wouldnt speakD. not speak39. It is high time the child _ to the hospital.A. is sent B. would be sentC. be sent D. were sent40. If it _ so hard，wed go to town.A. isnt raining B. werent rainingC. doesnt rain D. has
