1、八、情态动词和虚拟语气I.情态动词基本用法情态动词 用 法 否定式 疑问式 简答式cancan not / cannot /cant docould能力（体力，智力，技能）允许或许可（口语中常用）可能性（表猜测，用于否定句或疑问句中）couldnt doCando? Yes,can.No,cant.may may not do Maydo? Yes,may. No,mustnt/cant.might可以（问句中表示请求）可能，或许（表推测）祝愿（用于倒装句中）might not do Mightdo? Yes,mightNo,might not.must必须，应该（表主观要求）肯定，想必（肯定
2、句中表推测）must not/mustnt do Mustdo? Yes,must.No,neednt/dont havehave to只好，不得不（客观的必须，有时态和人称的变化）dont have to do Dohave to do?Yes,do. No,dont.ought to应当（表示义务责任，口语中多用should）ought not to/oughtnt to doOughtto do? Yes,ought. No,oughtnt.shall用于一三人称征求对方意见用于二三人称表示许诺、命令、警告、威胁等shall not/shant do Shalldo?Yes,shall.
3、 No,shant.should应当，应该（表义务责任）本该（含有责备意味）should not/shouldnt doShoulddo?will will not/wont dowould意愿，决心请求，建议，用在问句中would 比较委婉would not/wouldnt doWill/Woulddo? Yes,will. No,wont.dare敢（常用于否定句和疑问句中）dare not/darent do Daredo?Yes,dare.No,darent.need需要,必须（常用于否定句和疑问句中）need not/neednt do Needdo? Yes,must. No,ne
4、ednt.used to过去常常（现在已不再）used not/usednt/usent to dodidnt use to doUsedto do?Diduse to do?Yes,used. No,use(d)nt. Yes,did. No,didnt.II.情态动词的重点知识表示能力的情态动词用can/couldA computer _ think for itself; it must be told what to do.A. cant B. mustnt C. may not D. might not表示许可时用 may/might ,can/could 都可以，但在问句中用 co
5、uld?或 might？ 以使口气委婉客气，其回答一定要用can 或 may，以使回答口气明确（must 表示一定，必须，mustnt 表示禁止，不许可） 。Could I call you by your first name? Yes, you_A. will B. could C. may D. mightJohnny, you _ play with the knife, you _ hurt yourself.A. wont/cant B. mustnt/may C. shouldnt/must D. cant/shouldnt表示“能力、许可”的 can和may在肯定句中 coul
6、d 不可以用来表示过去某一特定场合的能力，而要用 was/were able to。The fire spread through the hotel very quickly butEveryone _ get out.A. had to B. would C. could D.was able to在肯定句中都可以用来表示可能。在含义上 must 语气最肯定,may 表示的是事实上的可能性。Peter _ come with us tonight, but he isnt very sure yet.A. must B. may C. can D. will而 can 表示的是逻辑上的可能
7、性：Mary is in poor health. She can be ill at any times.在否定句中只能用 can 和 may。所以 cant 时用以代替 mustnt，语气比 may 更肯定。中文可以翻译为不可能。Michael _ be a policeman, for hes much too short.A. neednt B. cant C. should D. may表示“推断、判断”的 canmay,must在疑问句只能用 can，不能用may 和 must。He may be very busy now. Can he be very busy now?He
8、must be very busy now. Can he be very busy now?need need 作为情态动词只有一种形式，只用于否定句和疑问句。daredare 作为情态动词用时有两种形式：dare 和 dared 两个词形，除了可以用于否定句和疑问句外，还可以用于条件从句或表示怀疑的句子中。If he dare come, I will kick him out. I dont know whether hedare say.注意:He doesnt dare(to)answer the question.（否定句）Does she dare(to)enter the da
9、rk room?（疑问句）用于第一人称：征求对方的意见。 What shall we do this evening?shall 用于第二、三人称：警告、命令、允诺、威胁等。You shall fail if you dont work harder. 警告He shall have the book when I finish reading.允诺He shall be punished.威胁should劝告、建议、命令、应该做、道义上的责任。You should(ought to) go to class right away. I should(ought to) help him be
10、cause he is in trouble.请求、建议，would 比 will 委婉客气。 Would you pass me the book?表示意志、愿望和决心。 I will never do that again. They asked us if we would do that againwould 可表示过去反复发生的动作或某种倾向。During the vacation he would visit me every weekThe wound would not heal.（伤口老是不能愈合）will/ wouldwould 表示估计或猜想。 It would be a
11、bout ten when he left home. What would she be doing there?could+have done：本可以做而实际上未能做。 You could have done better, but you didnt try your best.cannot+ have done：表示对现在或过去行为的否定推测。 He cannot have been to that town.情态动词+have done的用法can+主语+ have done：表示对过去行为的怀疑或不肯定（用在疑问句中） 。Can he have got the book?might
12、(may)+ have done：对过去发生的行为不太肯定的推测。He may not have finished the work.If we had taken the other road, we might have arrived earlier.must+ have done：对过去发生的行为肯定的推测。其否定式为：cannot have done。You must have seen the film.You cannot have seen the film.neednt+ have done：本来不必要做的而实际上又做了。You neednt have watered the
13、 flowers, for it is going to rain.注意：didnt need to(have to)do：没有必要做而实际上也没有做I didnt need to clean the windows. My sister did it 2 hours ago.should(ought to)+ have done：本来应该做而实际上又没有做。其否定形式表示某中行为不该发生却发生了。You should have started earlier, but you didnt.She shouldnt have taken away my measuring tape,for I
14、 worked to use it.注意：He should have finished the work by now.（表推测）虚拟语气类 别 用 法 例 句与现在事实相反从句动词：过去式（be 用 were）主句动词：should/would/could/might+doIf he were here, he would help us.与过去事实相反从句动词：had+done主句动词：should/would/could/might+have+doneIf I had been free, I would have visited you.If 引导的条件从句 与将来事实相反从句动词：
15、过去式/should+ 动词原形/were+to do主句动词：should/would/could/might+动词原形If it should rain tomorrow, we would not go camping.省略 if的虚拟条件句将虚拟条件从句中的 were，had, should 放到主语之前，构成主谓倒装Should he come ,tell him to ring me up.Were I you, I would not do it.Had I been free, I would have visited you.不同时间的虚拟：各遵守各的规则If he had
16、listened to me, he would not be in trouble now.If he had told me yesterday, I should know what to do now.If I were you, I would have gone to her birthday party.混合虚拟条件句虚拟与陈述的混合：各遵守各的规则He could have passed the exam, but he wasnt careful enough. You should have come earlier. The bus left a moment ago.b
17、ut for+名词表示虚拟条件-But for your timely warning, we _ into great trouble.-You know were friends.A. would get B. must have got C. would have gotD. cant have gotwithout+名词虚拟条件 Without the air to hold some of the suns heat, the earth at night would be freezing cold.动词不定式虚拟条件 It would be only partly right t
18、o follow in this way.现在分词表示虚拟条件 Having known in time ,we might have prevented the accident.含蓄虚拟条件句过去分词表示虚拟条件句子或主句中的谓语动词的形式视具体情况而定。这是考查考生应变能力的最佳试题。Given more attention, the tree could have grown better.副词 otherwise 表示虚拟条件I was too busy at that time. Otherwise, I would have called you. 连词 but 连接的句子表示虚
19、拟条件He _fatter but he eats too little .A. would become B. would have become C. must become D. must have become as if/as though 引导的状语从句中动词用 did 或haddone 或 wouldcouldmight do。注意：as if/ though 引导从句中也可以用陈述语气：当说话者认为所述的是真实的或极有可能发生或存在的事实时：It sounds as if it is raining听起来像是在下雨。He talks as if he is drunk从他谈话的
20、样子来看他是醉了。与现在事实相反He talks as if he knew where she was与过去事实相反He talks about Rome as if he had been there before.与将来事实相反He opened his mouth as if he would say something.其它状语从句in order that/so that 引导的状语从句中动词用can/could/may/ might/ would 等+do Turn on the light so that we can see it clearly.demand, sugges
21、t, order, insist 后接的从句中动词为 should+do He suggested that we not change our mind.宾语从句 wish 后的从句中分别用过去式，过去完成式和should/would+do 表示与现在，过去和将来情况相反I wish I could be a pop singer.I wish I would have gone to Shanghai last month.主语从句在 It is necessary / important / strange thatIt is suggested / demanded/ ordered
22、/ requested that等从句中，谓语动词用 should+doIt is strange that such a person should be our friends.It is time that句型中动词用过去式或 should+do Its high time that we left/should leave.would rather 所接的从句中动词用过去式或者过去完成式 I would rather you stayed at home now.其它句型中 If only 句型中动词常用过去式或者过去完成式，表示强烈的愿望 If only our dream had
23、come true!1.I enjoyed the movie very much. I wish I _ the book from which it was made.A. have read B. had read C. should have read D. are reading2.You are late. If you _ a few minutes earlier, you _ him.A. come; would meet B. had come; would have metC. come; will meet D. had come; would meet3.The tw
24、o students talked as if they _ friends for years.A. should be B. would be C. have been D. had been4.It is important that I _ with Mr. Williams immediately.A. speak B. spoke C. will speak D. to speak5.He looked as if he _ ill for a long time.A. was B. were C. has been D. had been6.If the doctor had c
25、ome earlier, the poor child would not _.A. have laid there for two hours B. have been lied there for two hoursC. have lied there for two hours D. have lain there for two hours7.I wish that I _ with you last night.A. went B. could go C. have gone D. could have gone8.Lets say you could go there again,
26、 how _ feel?A. will you B. should you C. would you D. do you9.I cant stand him. He always talks as though he _ everything.A. knew B. knows C. has known D. had known10._ the fog, we should have reached our school.A. Because of B. In spite of C. In case of D. But for11.If you had told me in advance, I
27、 _ him at the airport.A. would meet B. would had met C. would have met D. would have meet12.Mike can take his car apart and put it back together again. I certainly wish he_ me how.A. teaches B. will teach C. has taught D. would teach13.I would have told him the answer had it been possible, but I _ s
28、o busy then.A. had been B. were C. was D. would be14.Hes working hard for fear that he _.A. should fall behind B. fell behind C. may fall behind D. would fallen behind17.My father did not go to New York; the doctor suggested that he _ there.A. not went B. wont go C. not go D. not to go20.You look so
29、 tired tonight. It is time you _.A. go to sleep B. went to sleep C. go to bed D. went to bed23._ today, he would get there by Friday.A. Would he leave B. Was he leaving C. Were he to leave D. If he leaves 1. Had it not been for the heavy fog, you _（就看到了美丽的塔）in the distance easily last Tuesday. (see)
30、 2. Were _（下雨）tomorrow, the meeting would be put off. (rain) 3. Which doctor _ （你建议请来） immediately? (suggest) 4. It_ (一定下着大雨)when he got back home, for he was wet all over. (rain) 5. What a pity! We _ (宁愿听取) our teachers advice yesterday. (would rather) 6. I_ (本想参加) your party, but I had to work ext
31、ra hours to preparea speech. (would like) 7. With a little more care you _(能避免) this traffic accident. (avoid) 8. When the police took the suspect to the police station, he insisted that he_ (没偷) the ladys purse and that he_ (释放). (steal, set) 9. How I wish I _ (被录取了) the key university. (admit). 10
32、. The weather turned out to be fine yesterday, I_ (本不需要那么麻烦)to carry my umbrella with me. (take) 11. The workers in the factory demanded that their pay _ (提高 20%). (raise) 12. When a pencil is partly in a glass of water, it looks as if it _ (断了). (break) 13.Many coal mine accidents_(本来可以避免的)if we ha
33、d followed the strict safety rules.(avoid)14.Look what mistakes Ive made, If only I_(听你的劝告).(follow)15. _(万一你被解雇), your health care and other benefits will not be immediately cut off.(fire)16.Luckily wed brought a map with us, _(没有它我们就会迷了路).(without)17.He would have helped us but that he_(没时间)at tha
34、t time.18.The suggestion that the mayor_(发奖)has been accepted by everyone.(present) 19. It is high time that we_ (采取措施) protect the environment. (measure) 20.He_help you (本来打算),but he had no time.(mean)21.If the weather had been more favorable , the crop_(会长得更好)now. (grow)22.What I advise is that_(你
35、们要安静)。(quiet)Keys: 15 BBDAD 610 DDCAD 1115 CDCAA 16 20 ACAAD 2123 DBC 1. would have seen the beautiful tower 2. it to rain 3. do you suggest be sent for 4. must have been raining 5. would rather have taken 6. would like to have attended 7. could have avoided 8. didnt steal, be set free 9. had been a
36、dmitted to 10. neednt have taken the trouble 11. be raised by 20 percent 12. were broken 13could have been avoided14.had followed your advice15.If you should be fired/ Should you be fired16.without which I would have got lost17.had no time 18.should present the prize 19.should take/took measures20.h
37、ad meant to 21.would be growing better 22.you should be quiet语法填空： 1.I would rather Tom_(come) tomorrow. 2.It seems as if it_(be) winter now. 3.What would have happened if you _(not help) her child？ 4.It is strange that he _ (think) so. 5.I wish I _(meet) my uncle yesterday. 6.Galileo insisted that
38、the earth_(move) the sun. 7.Supposing the weather _(be) bad, where would you go? 8.But for your help, I couldnt _(find) the place. 9.What do you think would happened if there _(be) no light in the day? 10.I was very busy yesterday, otherwise I _(go) to the party. 11.Without your help the old man_(no
39、t live) now. 12.It is high time you_(take) the medicine ,sir. 13.I wish I _( attend) the meeting yesterday.14.I wish I _(can) fly.15.He wished he _(not fall) in love with her before.16. I would rather you _(paint) the wall green next time.17.I would rather she _(not do) that.18.If only I _(take) you
40、r advice.19. If only I _(be) a bird!20. It was John who broke the window. Why are you talking to me as if I _ (do) it. 21. My mom suggests that we _ eat out for a change this weekend. 22. Dont handle the vase as if it _(be) made of steel. 23. If he _ (follow) my advice, he wouldnt have lost his job.
41、 24. We took a taxi to the lecture hall. Otherwise we _ (be) late for the meeting. 25. If we _ (book) a table earlier, we wouldnt be standing here in a queue. 单句改错：1. If I was you, I would run faster.2. If I live near my office, I would walk to work.3. I know nothing about the film. If I knew about
42、it, I will tell you.4. If she worked hard enough, she would have passed the English exam.5. If it were not rain tomorrow, they might go to the Great Wall.6. If it were not for the fact that she couldnt sing, I would invite her to the party.7. Should the weather fine, we might go on a trip.8. She was
43、 very busy yesterday, otherwise she would come to the meeting.9. I wish I was as tall as you.10. How I wish I can pay a visit to Paris.11. He wishes that he studied French instead Japanese in the college.12. I would rather you pay me now.13. Its high time that we go to bed.14. Look at the trouble I
44、am in! If only I followed your advice.15. If you asked him yesterday, you would know what to do now.16. He would be a good sportsman now if he trained regularly.1. came 2. were 3. hadnt helped 4. should think 5. had met 6. moves 7. were 8. have found9. were 10. would have gone 11. wouldnt lives 12.
45、took 13. had attended 14. could 15. hadnt fallen 16. pointed 17. hadnt done 18. had taken 19. were 20. had done 21.should 22 .were 23.had followed 24.would have been 25.had booked1. waswere 2. livelived 3. willwould 4. she+ had 5. not+ to 6. couldnt cant7. weather+ be 8. would + have 9. waswere 10. cancould 11. insteadof 12. paypaid 13. gowent 14. I + had 15. you+ had 16. he + had1. were 2. could walk 3.(should) do 4. ended 5. It 6. (should).take 7would be destroyed 8. it 9. is taken 10.will improve 11.would become 1Should 2Can 3cant 4
