情态动词讲义及练习

1、情态动词情态动词表示说话人对某一动作或状态的态度，可以表示“可能” 、“可以”、“需要”、“必须” 或“应当”等之意。情态动词没有人称和数的变化。但不能单独作谓语动词用，必须和不带 to 的不定式连用构成 谓语动词。只有情态动词 ought 要和带 to 的动词不定式连用，在句中作谓语用。将情态动词置于主语之前即构成其疑问式，在情态动词之后加 not 既构成其否定式。现将各 情态动词的基本用法分述如下：1、can和could (could为can的过去式)的基本用法(1) 表示能力，如： He can speak English better than you.(2) 在疑问句和否定句中表示“

2、怀疑” 、“猜测”或“可能性” ，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。如： Can this green bike be Liu Dongs?Where can (could) they have gone to? 他们会去哪儿了呢？He can t(couldn t) 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？(3) 表示“许可”时 can 可以和 may 换用，如： You can (may) go home now.(4) 表示请求对方的许可 ,如: Can I go now?如果

3、要表示语气婉转，可用could代替can,这时could不再是can的过去式，如： Could you come again tomorrow?(6) can 和 be able to 都可表示能力, 两者在意思上没有什么区别。 但是 can 只能有现在式和 过去式，而be able to则有更多的形式， be able to指经过努力才能够”。如： He will be able to do the work better.(7) can, could 后接完成式的用法： 在否定句或疑问句中表示对过去发生过的事情的“怀疑” 或“不肯定” 的态度, Couldhe have said so?

4、在肯定句中，可以表示过去可能做到而实际并没做到的事情，有“劝告”或“责备” 的语气。如： When did you answer her letter? Only yesterday. Its too late. You could have answered it earlier, I am sure.(8) 用于肯定句中,表示理论上,习惯上,经验上的, 理论上或是逻辑判断上可能性 , 不是实际上的可能性 .Accident can happen at any time .It could be very interesting to do out for a drive .The temp

5、erature can fall to -60C , that is 60 C below freezing.气温可降至 一60C,也就是零下 60C。He can t(could n t) have eno ugh money for a new car.他不可能有足够的钱买新车。 You mustn t smoke while you re 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。(9) 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 / weatble to则表

6、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 didn t fee llike 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。(10 ) cant 表示不可能； may not 表示可能不2、may和might (might为may的过去式)的基本用法(1) 表示允许 (第二人称 )或征询(第一人称 )对方许可,有“可以”之意,如： You m

7、ay use my dictionary.在回答对方说“可以做某事”或“不可以做某事”时，一般多不用may或may not，以避免语气生硬或不容气。而用比较婉转的说法进行回答。如： May I use this dictionary? Yes, please. 或 Certainly. 在请求对方许可时,如果Might I?就比用May I?语气更婉转些，如： May I have a look at your new computer? 但是表示“阻止”或“禁止”对方做某事时, 要用 must not 代替 may not,如： May we swim in this lake? No, y

8、ou mustn t. It s too dangerous.(2) may 或 might 都可以表示推测,可能性,表示“或许” 、“可能”之意,如果用 might 表示 可能性，则语气更加不肯定，与 can(表示理论上，经验上，逻辑关系上)相比，may , might用于事 实上的可能性 。如： They may (might) be in the library now . 一般情况下不用于疑问句中 , 但 可以用于否定句中。 May not 表示“可能不” 之意, can not 表示“不可能” 之意。 The story may not be true.(3) 用于祈使句中表示祝愿,

9、如：May you succeed.May God bless you(4) maymight as well do sth ,做也无妨，只好做某事，倒不如做某事，如： There is nothing to do ， I may as well go to bed.(5) may well 可能,很可能Liza _ well not want to go on the trip she hates traveling.A. will B. can C. must D. may(6) may, might 后接完成式的用法 表示对过去某事的推测，认为某一件事情在过去可能发生了。如果使用migh

10、t，语气就比较婉转或更加不肯定，如： Mary might have learned some Chinese before. 可以表示过去本来可以做到，而实际没有做到的事情，有“劝告”或“责备”的语 气，如： You didnt do the work well that day. You might have done it better.3、must的基本用法must表示“必须”、“应该”之意，其否定式must not,缩写形式为 must nt，表示“不应该”，“不准”、“不许可”或“禁止”之意，如： We must study hard and make progress every

11、 day. You mustnt touch the fire.(2) 对以must提出的疑问句，如作否定回答时，要用need nt或用dont (does nt) have to (不 必) 来回答，而不用 must nt，因为must nt表示的是“禁止”或“不许可”之意，如： Must we finish the work tomorrow? No, you neednt (dont have to), but you must finish it in three days.(3) 在肯定句中must可以表示推测，表示“一定”或“必定”之意，如： Whose new bike can

12、it be? It must be Liu Dongs. I know his father has just bought him a new one.(4) must 后接完成式的用法：表示对过去某事的推测，认为某事在过去一定做到了，女口： Liu Dong isn t in the classroom. He must have gone to the library.(5) 在反意疑问句中，其后面的反问部分取决于must 后面的动词形式：You must be a new comer ,arentyou?(6) if you must (do sth) 表示虽不赞同但可允许。 “如果你

13、一定要那么做， 类似的句式有： why must you? 为什么非要那样做 Must you ?非要那样做吗？， 表示说话者对对方的坚持生气或不满。If you must leave , do it quietly .Can I smoke ?If you must .(7) 用于发生了某种于说话人的愿望相反、不受欢迎的事时，意思是“偏偏”、 “偏要 ”。Why must he do it that way?Why must it rain on Sunday?4、have to 的基本用法：(1) have to和must的意义相近，只是must侧重表示说话人的主观看法，而have to则

14、表示客观需要，如： I must study hard .I had to give it up because of illness.(2) 在口语中，用 have got to 来代替 have to(3) have to 可以与其它的情态动词使用，但 must 不行5、ought to的基本用法(1) 表示根据某种义务或必要或暗理推断“应当”做某事，语气比should强，比must弱，Should 侧重从说话人个人看法这一角度来讲，倾向表示忠告。例如： Everyone ought to obey the traffic regulations.(2) 表示推测，注意与 must表示推测

15、时的区别：He must be home by now .( 断定他已到家 )， He ought to be home by now .( 不十分肯定 )，This is where the oil must be.( 比较直率 ) ， This is where the oil ought to be. ( 比较含蓄 ) ；(3) “ought + have+ 过去分词”表示过去应做某事而 实际未做，有责备的含义。例如： You ought to have helped him. (but you didn 这时， ought)t 与 should 可以互相换用。注意，在美国英语中 oug

16、ht to 用于否定和疑问句时 to 可以省略。例如： Ought you smoke so much?You oughtn stmoke so much.7、dare的基本用法(l) dare (dared 为其过去式 ) 作情态动词用时，主要用于否定句，疑问句和条件从句中，如： Dared he bread the traffic regulations again?(2 )在现代英语中 dare 常用作行为动词，其变化与一般行为动词相同，如： She dares to stay at home alone at night.We should dare to give our own o

17、pinion. 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 he II come again.我想他会再来的。(I dare say为固定习语)8、need的基本用法一， need 作情态动词用时，主要用于否定句和疑问句中，特别是表示“必须，有必要”只 能用在疑问句子中如： He neednt worry about us now.二，need也可作为行为动词用，可用于肯定句，否定句和疑问句中，其后可接名词、代词、 动名词或带 to 的动词不定式为其宾语。如： You need to practise reading

18、 aIoud every day.You dont n eed to do it yourself.你不必亲自做这件事。We need to teII them the news. 我们需要把这消息告诉他们。The tabIe needs painting (to be painted.). 桌子需要油漆一下。三，neednt后接完成式可以表示过去做了一件本来不必要做的事情，如： Did you answer the Ietter yesterday? Yes, I did. But you needn t have answered it.9、shall的基本用法一， shall 用作情态动

19、词时， 用于第二、 三人称， 表示说活人的意愿， 可表示 (1) “命令” (2) (3) “警告” (4) 根据条例、规章、约定、合同应尽的责任或义务， “强制”、“威胁” (5)郑重的 “许诺”，“允诺”等意，如： He shall go first, whether he wants to or not.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

20、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) 二，在疑问句中， shall 用于第一、三人称，表示说话人的征询对方意见或请求指示， 如： Shall I open the door?10、should的基本用法一，should作为情态动词可以表示 建议”或劝告”，有应该”之意，女口： You should learn from each other.二， should 后接完成式表示过去没有做到本来应该做的事情，或是做了本来不应该做的事 情。如： You should have gi

21、ve him more help.三，表示惊讶 ,吃惊 . 译成 “竟然 ”To my surprise , my deskmate should have failed the exam.四，用于 if 条件装语从句中引导的与将来事实相反的虚拟语气的句子中句子中fired, your health care and other benefits will not be immediately cut off.A. Would you be B. Should you beC. Could you beD. Might you be11、will 的基本用法(1) 用于各人称，可以表示“意志”

22、或“决心”，如： I have told him again and again to stop smoking, but he will not listen.(2) 在疑问句中用于第二人称，表示说话人向对方提出请求或询问对方的意愿，如： Will you please tell me how to get to the Capital Gymnasium?(3) will 可以表示目前，现在一种习惯性的动作，有“总是”或“会要”之意，或不耐烦之 意。如： The boy will sit there hour after hour looking at the traffic go by.

23、Every morning he will have a walk along this river.Fish will die out of water. 鱼离开水就不能活。 那男孩常常坐在那里好几个钟点，看着车辆行人通过。The door won t Open.这门总是打不开。(生气，不满意)The ink won tcome out. ( 不耐烦 )。12、would的基本用法(1)would 作为 will 的过去式，可用于各人称，表示过去时间的“意志”或“决心” ，如： He promised he would never smoke again.(2) 在疑问句中，用于第二人称，表

24、示说话人向对方提出请求或许问对方的意愿时，比用 will 的气更加婉转，如： Would you like some more coffee?在日常生活中，学用I would like to”表示我想要”或我愿意”之意，以使语气 婉转，如： I would like to do Ex.2 first.(4) would可以表示过去的习惯动作，比used to正式，并没有“现已无此习惯”的含义。如： Last year our English teacher would sometimes tell us stories in English after class.During the vac

25、ation he would visit me every week.(5) 表料想或猜想，如： It would be about ten when he left home.What would she be doing there?/ I thought he would have told you about it.(6) would 和 used to1) 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.过去人们认为地球是平的。 (现在人们不这么认为。

26、)She would go out for a walk in the morning when she was in the country.在乡下时，她总是在早晨去散会儿步。 (可能现在仍有散步的习惯。 )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。He used to / wouldmoke while writ in g.过去他写东西时常抽烟。She used to be fat. 她过去很胖13、used to, had better, would rathe的用法(1)used to 表示过去的习惯动作或状态，现在已不存在，在间接引语中，

27、其形式可不变，例如： He told us he used to play foot ball when he was young .在疑问句、 否定句、 否定疑问句或强调句中， 可有两种形式。 疑问句： Did you use to/ Used you to go to the same school as your brother? 否定句：I usedn t to / didn t use to go there. 也可写n 作 usen；t) 否定疑问句： Usen tyou to/ Didn tyou use to be interested in the theatre? 强调句：

28、 I certainly used to/ did use to smoke, but it was a long time ago. ；其反意疑问句或简略回答中， 也有两 种形式： She used to be very fat. didn t she?/ use(d)n t she? Did you use to pYleasy, cIhdeids.s/?Used you to get up early in the morning? Yes, I did./ used to.(2)had better 意为“最好” ，后接不带 to 的不定式，例如： We had better go n

29、ow . Yes, we had (wed better/ we had better)./Hadn t we better stop now? (Had we better not stop now?)I think I d better be go（用于进行时态，表“最好立即”You had better have done that （用于完成时态，表未完成动作）注： had better 用于同辈或小辈，对长辈不可用。（3）would rather 意为“宁愿” ，表选择，后接不带 to 的不定式， 如： I d rather not say anything./Would you r

30、ather work on a farm?/ Wouldn t you rathertasy here? No, I would not . I d rather go there. 由于 would rather 表选择，因 而后可接 than， 例如： I would rather work on a farm than in a factory.I would rather watch TV than go to see the film/I would rather lose a dozen cherry trees than that you should tell me one l

31、ie./I d rather you didn t talk about this to（句n中0的e. d rather 不是情态动词，would 在此是表愿望的实义动词 ），其后面必须用虚拟语气，即过去时。专项练习（一）1. I you, because I thought I must be wrong.A. dare not ask B. dare not to ask C. dare not asking D. dare to not ask2. There some flowers in the garden.A. were used to be B. used to be C.

32、uses to be D. used to be having3. “ take it out? ” “ | smrry, you. ”A. Could couldn t B. Might might not C. Could canD. Maycan t4. You were stupid to climb the tree. You hurt yourself.A. mayB. mightC. will D. might have5. You those letters. Why didn t you ?A. should post B. should have posted C. mus

33、t have posted D. ought to post.6. All the lights are on, the Smiths up.A. must get B. is getting C. must be getting D. would get7. He lead a horse to the water but he not make it drink.A. will can B. mayc anC. maydares D. dare can8. “ Needwe do this job now?”“ Yes_,. ”A. you need B. you should C. yo

34、u must D. you can9. to have lunch with us today?A. Do you likesB. Would you likeC. Will you likedD. Have you liked10. He said that you watch TV all the evening if you wished.A. may B. must C. can D. might11. -s Joh n coming by train? -He should, but henot. He likes drivi ng his car.A. must B. can C.

35、 need D. may12. Peter come with us tonight, but he isn t very sure yet. A. must B. can C. may D. will13. Michaelbe a policeman, for he s much too short.A. need ntB. cant C. should nt D. wont14. I thought yoube hun gry, so I have brought you some cakes.A. may B. might C. can D. could15.1 won der how

36、hethat to the teacher.A. dare to say B. dare say ingC. not dare say D. dared say16. Come on! Wehurry because there isn t much time left.A. mayB. mustC. canD. n eed17. Amy did best in the En glish test. Shehard last week.A. must have work ing B. should have workedC. should workD. must work18. The fir

37、e spread through the hotel very quickly but every oneget out.A. had toB. wouldC. couldD. was able to19. I stayed at a hotel while in New York. -Oh, did you? Youwith Barbara.A. could have stayed B. could stay C. would stay D. must have stayed20. It s nearly seven o clock . Jackbe here at any moment.A

38、. mustB. n eedC. shouldD. can答案：1.A2.B3.D4.D5.B6.C7.B8.C9.B10.D11.D12.C13.B14.B15.D16.B17.A18.D19.A20.专项练习（二）1. Jeanhave kept his promise. I won der why he cha nged his idea.A. must B. should C. n eedD. would解析：选B. “should have过去分词”表示过去本来应该（但没能）做某事” ；keep one s promised 为“信守诺言”。2. Janehave come to t

39、he party, but she not find the exact time.A. could; couldB. might; couldC. should; couldD. should; would解析：选A. “ could have+过去分词表示过去本来应该（但没能）做某事”。3. So many mistakes in your homework! You more careful.A. may beB. had to C. would beD. should have bee n解析：选 D. “You should have been more careful意为:你本来应

40、该更细心的。4. Her brother be at home now, because he was seen playing basketball in the stadium justnow.A. must n t B. n eed n tC. can t D. should nt解析：选C. can t be at hom意为：不可能在家。5. -1 can t understand why our boss is lateHe the early bus.A. could miss B. may have missed C. can have missed D. might miss

41、解析：选B. “ may have+过去分词”表示对过去动作的判断，意为：可能做了某事。注意：can表示可能时，只能用于疑问句和反问句。6. She did nt an swer the phone, sheasleep.A. may beB. must beC. should have bee nD. must have bee n解析：选D.表示：对过去发生的事情的肯定推测。7. The little girl s eyes were red. She.A. may cry B. must cry C. must be cried D. must have been crying 解析：

42、选 D. 意为：她刚才肯定一直在哭。对过去某事正发生的推测。8 He his supper now, for the dining hall is still closed.A. can t be havingB. needn t be havingC. mustn t be havingD. shouldnt be having 解析： 选 A. 对现在正在发生的事情的否定推测。9 I parked my bike behind the building, but now it is gone. It .A. may be stolen B. must be stolen C. must h

43、ave been stolenD. must have stolen解析： 选 C. 对过去发生的事情 的肯定推测的被动式。10. Mr. Blackgo to work by ferry before the bridge was built?A. Did; used to B. Use; to C. Did; use to D. Does; use to 解析：选C. used to do的疑问式，可以是 Used+主语+to do ?或Did +主语+use to do?11. The hotel is only a stones throw away, you take a bus.A

44、. need not toB. not need toC. dont need D. need not解析： 选 D. 说话人认为不必要乘车 , need 为情态动词。12. I am busy now, my brother do it for you ?A. WillB.ShallC.MustD.May解析： 选 B. 在疑问句中 shall 用于第三人称，也表示征求意见。13. -You needn t do it right now, need yo-u-?Yes I am afraid I .A. needB.needn t C. mustD.mustn t解析：选C. Yes的意思

45、是：不。意为：恐怕我必须现在就做。14. My English-Chinese dictionary has disappeared . Who have taken it? （2003 年上海春季高考 ）A. should B. mustC. couldD. would解析： 选 C. could/can have done 用于否定推测和疑问推测。15. -The room is so dirty.we clean it?Of course. （2003 年北京春季高考 ）A WillB. ShallC. Would D. Do解析： 选 B. shall 用在疑问句中，常用于第一，三人称

46、， 表示征求意见或请求指示。16. If you have something important to do, you waste any time.A. needn t B. mustn t C. may notD. won t解析： 选 B. 根据句意用 mustnt17. If you want to borrow a football after school, your student cardhere.A. has to leave B. must leave C. has to be leftD. must be left解析： 选 C. have to 表示客观需要， mus

47、t 表示主观需要。学生证必须放在此是客观需要。18. “ Did you scold him for his carelessness?“Yes, but”it ”A. I d rather not doB. I d rather not have doneC. I shouldn t do D. I d better not do 解析： 选 B. would rather 加完成时表示对完成了的或过去了的事情的态度。 意为： 当时是不情愿 做的。19. “ Dont get near to it . It is too dangerous! “ ” .A. Yes, I won t B.

48、No, I dontC. No, I cantD. No, I won t解析： 选 D. A 为错误的表达方式； B 和 C 没有直接回答对方的问候。20. He must be in the classroom, he?A. mustn t B. can t C. isn tD.can解析：选 C. 对表否定的 must 进行反意疑问时，要用句子的实义动词21. He be in the garden. He must be in the room.A. can t B. mustn t C. will not D. may not解析：选A.否定推测用can不用must nt22. “D

49、o you have to leave now?“”Iam very sorry, but I really.”A. can tB. haveC. should D. must解析：选D.回答have to的疑问句用must作肯定回答。23. “Let s go to the library, shall we? “ ”_? ”A. No, I can t B. Yes, I willC. Yes , thank you D. No, we d better not解析：选 D. A,B,C 都不能回答 shall we, 此处 D 的语气比较婉转客气。24. “Can I take it a

50、way? ”“ You better not.”A. shouldB. couldC. wouldD. had解析：选 D. had better 与不带 to 的不定式构成谓语，可以变成疑问句：Hadnt you bette-r-25. You have brought your camera. They all had theirs with them.A. couldn tB. needn t C. wouldn tD. mustn t解析：选 B. 本来不必要做某事 .26. See who is there!it be May?A. MayB. MustC. CanD. Will解析

51、：选 C. 表推测时 A，B 都用作疑问句。27. John be a basketball player. He is much too short.A. mayB. mustn tC. can tD. should解析：选 C. 断然的不定推测用 cant28. The Chinese teacher looks so pale. She be ill.A. mustB. mustn t C. canD. need解析：选 A. 表示有把握的肯定推测用 must29. Somethingto save our earth. Do you think so?A. can doB. must

52、doC. has to doD. must be done解析：选D. “something must be done意为：必须采取措施。30. Look at what you have done! You be more careful.A. ought B. canC. wouldD. should解析：选 D. ought 后应用 to专项练习（三）1. Has Li Lin started? He said he would join in the party. He . He is a man of keeping his word.A. could have left B. mu

53、st have left C. can t comeD. won t be comngi2. May I park my car here? No, you . No car is allowed to park here.A. may not B. needntC. mustn tD. daren t3. Excuse me, could you tell me where the Yajia Supermarket is? It s two blocks straight ahead. You miss it.A. mustn tB. can tC. needn Dt. shouldn t

54、4. I saw Mr. Sun at Tongyu Station this morning. You . He s still on holiday in Hawaii.A. c ouldn t haveB. mustn t haveC. shouldn tD. needn t5. How about paying a visit to Dr. Wang, our former Chinese teacher? Good idea. I will e-mail him today so that he know to expect us.A. shall; whyB. could; whe

55、n C. would; whatD. will; how6. Everything has two sides. Beautiful songs, sometimes, be just noise to others.A. must B. may C. should D. could7. Someone my umbrella. I found it wet yesterday.A. must be using B. must have usedC. must use D. must have been using8. How dangerous it was! Yes, but for th

56、e passer-by s quick action, the girl .A. was drowned B. could have been drowned C. had drowned D. should be drowned9. You scold such a pupil who always keeps silent so seriously that you hurt him.A. should; canB. may; will C. mustn t; may D. can t; must10. Why does Alice know so much about Angkor Wat? She