非常重要情态动词

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1、情态动词专题一概述助动词（auxiliary）主要有两类：基本助动词（primary auxiliary）和情态助动词（modalauxiliary）。基本助动词有三个：do, have和be;情态助动词有十三个：may, might; can, could;will, would; shall, should; must, n eed, dare, used to, ought to.上述两类助动词的共同特征是，在协助主动词构成限定动词词组时，具有作用词的功能：1）构成否定式：He didn go and neither did she.The meeting might not start

2、 until 5 o clock.2）构成疑问式或附加疑问式：Must you leave right now?You have been learning French for 5 years, haven you?3）构成修辞倒装：Nowhere can he obtain any information about his sister.Hardly had he arrived when she started complaining.4）代替限定动词词组：A: Who can solvethis crossword puzzle?B: Tom can.二情态助动词的特征基本助动词与情

3、态助动词最主要的区别之一是，基本助动词本身没有词义，而情态助动词则有自己的词义，能表示说话人对有关动作或状态的看法，或表示主观设想：What have you bee n doi ng si nee?（构成完成进行体，本身无词义）I am afraid I must be going.（定要）You may have read some acco unt of the matter.（或许已经）现将情态助动词的各种形式列表如下:冃定式否定式简略否定式may mightmay not might notmayn t mightn tcan couldcan not, cannot could n

4、otcan t couldn twill, llwould, dwill not, ll notwould not, d notwontwouldn tshall shouldshall not should notshan t shouldn tmustmust notmustn tn eedn eed notneedn tdaredare notdaren tused toused not todidn t use(d) to usedn t toought toought not tooughtn t to三情态助动词的意义和用法情态助动词反映说话者对其表述是否真实和可能的程度。但不同的

5、情态助动词本身所包含的意义和用法又不同，下面逐个分析。1) can和could的用法1. 表示能力或客观可能性，还可以表示请求和允许。如：Can you finish this work toni ght?Man cannot live without air.Can I go now? Yes, you can.注意：could也可表示请求，预期委婉，主要用于疑问句，不可用于肯定句，答语应 用can (即could不能用于现在时态的简略答语中)。如：Could I come to see you tomorrow?Yes, you can.(否定答语可用 No, I m afraid not

6、. can表示能力时，还可用 be able to代替。如：I ll not be able to come this after noon.2. 表示惊异、怀疑、不相信的态度。(主要用在否定句、疑问句或惊叹句中)Can this be true?How can you be so careless!This cannot be done by him.3. “ can(culd) + have +过去分词的疑问或否定形式表示对过去发生的行为怀疑或不 肯定。如：He cannot have been to that tow n.Can he have gotthe book?2) may和mi

7、ght的用法1. 表示许可。表示请求、允许时，might比many的语气更委婉一些，否定回答时要用mustn表示不可以”、禁止”阻止”之意。如：You may drive the car.Might I use your pen? No, you mustn. t用May I .征询对方许可在文体上比较正式，在口气上比较客气。在日常口语中， 用Can I .征询对方意见在现代口语中更为常见。2. 用于祈使句中表示祝愿。如：May you succeed!3. 表示推测、可能(疑问句不能用于此意)。He may be very busy now.4. “ may(might) + have +过

8、去分词表示对过去发生的行为的推测。如：He may not have finished the work.3) must和have to的用法1. 表示必须、必要。如：You must come in time.回答must引出的问句时，如果是否定的回答，不能用must n，而要用need nt do n thave to。 Must we hand in our exercise books today? Yes, you must (No, you don t have to.)2. must be +表语的结构表示推测，它的否定或疑问式用can代替must。This must be yo

9、ur pen.3. must + have +过去分词的结构常用在肯定句中，表示对过去发生的行为的推测。 它的否定或疑问式用 can代替must。He must have beento Shan ghai.4. have to的含义与 must相似，两者往往可以互换使用，但have to有各种形式，随have 的变化而定。must与have to有下列几点不同： 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。如：The play is not interesting. I really must go now.I had to work whe n I was your

10、 age. must 般只表现在，have则有更多的时态形式。 二者的否定意义不大相同。如：You mustn go.你可不要去。 You don t have go.你不必去。 询问对方的意愿时应用 must。如：Must I clea n all the room?4) dare和need的用法1. need表示 需要”或 必须”作情态动词时，仅用于否定句或疑问句中，在回答句中 一般用 must, have to, ought to,或 should 代替。如：You needn tome so early. Need I fin ish the work today?Yes, you m

11、ust注意：needn t +不定式的完成式表示本来不必做某事而实际上做了某事”女口： You needn t have waitedr me.2. Dare作情态动词时，主要用于疑问句、否定句和条件从句中，一般不用在肯定句中。 如：How dare you say I m unfair. He daren speak English before such a crowd, dare he?3. Dare和need常用作实义动词，有时态、人称和数的变化，所不同的是，作实义动词时，在肯定句中，dare后面通常接带to的不定式，在否定和疑问句中，dare后面可接带to或不带to的不定式。如：I

12、dare to swim across this river.He does not dare to an swer.Don t youdare to touch it!I won dered he dare (to) say that.He needsto finish it this eve ning.5) shall 和 should 的用法1. Shall用于第一人称，表示征求对方的意愿。如：What shall we do this evening?2. Shall用于第一、第三人称疑冋句中，表示说话人征求对方的意见或向对方请示。女口：Shall we begi n our less

13、 on?When shall he be able to leave the hospital?3. Shall用于第二、第三人称，表示说话人给对方命令、警告、允诺或威胁。如：Youshall fail if you don t work harder.（警告）He shall have the book when I finish reading.（允诺）He shall be punished.（威胁）4. Should表示劝告、建议、命令，其同义词是ought to;在疑问句中，通常用 should 代替ought to。如：You should go to class right aw

14、ay.Should I ope n the win dow?Should的含义较多，用法较活，现介绍三种其特殊用法。请看下面的句子： I should think it would be better to try it again.我倒是认为最好再试一试。 You are mistaken, I should say.依我看，你是搞错了。 I should advise you not to do that.我倒是劝你别这样做。 This is something I shouldhave liked to ask you.这是我本来想问你的。从以上例句可以看出：情态动词should用于第一

15、人称时可以表示说话人的一种谦逊、客气、委婉的语气。Should还可以用在if引导的条件从句，表示一件事听起来可能性很小，但也不是完全没有可能。相当于万一”的意思。从句谓语由should加动词原形构成，主句谓语却不一定用虚拟语气。如： Ask her to ring me up if you should see her.你万一见到她，请让她给我打个电话。 If you should change your mind, please let us know.万一你改变主意，请通知我们。 Should I （If I should） be free tomorrow I will come.万一我

16、明天有时间，我就来。此外，Why（or How） + should 结构表示说话人对某事不能理解，感到意外、惊异等 意思。意为竟会”女口： Why should you be so late today?你几天怎么来得这么晚？ 一Where is Betty living?贝蒂住在哪里？How should I know? 我怎么会知道呢？ I don t knowwhy you should think that I did it.我真不知道你凭什么认为这件事是我干的。5. “should + have +过去分词结构一般表示义务，表示应该做到而实际上没有做到， 并包含一种埋怨、责备的口气。

17、如：She should have finishedit.I should have helpedher, but I n ever could.You should have startecfearlier.6） will和would的用法1. 表示请求、建议等，would比will委婉客气。如：Would you pass me the book?2. 表示意志、愿望和决心。如：I will n ever do that aga in.They asked if we would do that aga in.3. 用“will be和will（would） + have +过去分词的结构

18、表示推测，主要用于第二、三人称。前者表示对将来情况的推测，后者表示对已经完成的动作或事态的推测。如:This will be the book you want.He will have arrived by now.The guests would have arrived by that time.I thought you would have finishedthis by now.4. Would可表示过去反复发生的动作或某种倾向。Would表过去习惯时比used to正式, 并没有 现已无此习惯”的含义。如：The wound would not heal.During the v

19、acati on he would visit me every week.5. 表料想或猜想。如：It would be about ten whe n he left home.What would she be doing there?I thought he would have told you all about it.7）ought to的用法1. Ought to表示应该。如：You ought to take care of him.2. 表示推测。注意与 must表示推测时的区别：He must be at home by now.（断定他已至U家）He ought to

20、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 to + have +过去分词表示过去应做某事而实际未做。如：You ought to have askechim （but you didn t）.这时，ought to和should可以互相换用。注意：在美国英语中，ought to用于否定句和疑问句时，to可以省略。如：Ought you smoke so much?You oughtn stoke so much.8）us

21、ed to, had better, would rather 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，其形式可不变。如：He told us he used toplay football whe n 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 togo to the same school as your brother?Used you to go to the same school as your brother?否定句I usedn t go there.I didn t u

22、se go there.Usedn 亦可拼作 usen ，但发音皆为 ju:znt。否定疑问句Usen t you tbe in terested in the theatre?Didn t you use to interested in the theatre?强调句I certainly used tosmoke, but it was a long time ago.I certa inly 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 she

23、?(正式)/ use(d)n she? (口语)Did you use to play chess? Yes, I did.Used you to get up early in the morning? Yes, I did. (Yes, I used to)2. Had better意为 最好”后接不带to的不定式。如： We had bettergo now. Yes, we had (we d better / we had better).Hadn t we bettestop now? (Had we better not stop no w?)I think I d bettbe

24、 going.(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 best与had better同意，但较少用。You 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 ratheiot say anything.Would you rather work on a farm? Wouldn t yoj rather stay here? No, I would not. I d rather go the re由于would rat

25、her表选择，因而后可接than。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 doze n cherry trees than that you should tell me one lie.I d ratheyou didn talk about this to anyone.(句中的d rathe不是情态动词，would 在此是表愿望的实义动词)四强化训练1) 单项选择1. Youhand it

26、in at once, you may hand it in tomorrow.(A) need nt(B) may not(C) cant(D) must not2. That must be a mistake. No it a mistake.(A) must not be(B) n eed nt be3. Yougo no w. Its gett ing late.(A) had rather(B) would4. Since the bus is crowded, we.(A) had better walk to home(C) had better walk home5. You

27、come in now, Mary! Its getting cold!(A) had better.had better(C) had better.would rather6. When I was a boy, Ichocolate.(A) would like(B) was used to like(C) cann ot be(D) would not be(C) had better(D) would(B) have better walk home(D) had better to walk homeIgo on playing in the garden.(B) would ra

28、ther.had better(D) had better.would have better(C) should like (D) used to like7. I was nt supposed to go to the movies, but Imyself.(A) cannot help(B) could nt but(C) had to help (D) could nt help8. Look ing at my determ ined face, the big boypick up the fight.(A) dares not(B) dare not(C) does nt d

29、are(D) dares not to9. He bega n to write two hours ago. Hehave fini shed the article now.(A) must(B) ought(C) ought to(D) had to10. Youto the meet ing this after noon if you have someth ing importa nt to do.(A) n eed nt to come (B) dont n eed come (C) dont n eed coming(D)n eed nt come11. you be here

30、 at eight oclock tomorrow morning?(A) Would(B) Should(C) Can(D) Could12.I have a talk with the Party Secretary now?(A) Will(B) Did(C) May(D) Can13. Youread that article if you dont want to.”(A) need nt(B) mustn t(C) have nt(D) can t14. When the storm comes all win dows.(A) ought to close (B) ought t

31、o be clos ing (C) ought to be closed (D) ought to closed15. Ime what happe ned.(A) would like you tell(B) would like you to tell(C) would like you telli ng(D) would like you that you tell16. I hope you can visit my country soon, becauseto show you some of the beautiful placesn ear my home.(A) I like

32、(B) Id like(C) I will like(D) I shall like17. Shefor yesterdays test, but she didn t.(A)should have studied (B) would study (C) might be study ing (D)must have studied18. Hebreakfast at eight oclock whe n he lived alone. But no wadays heit at seve n.(A) was used to have . is hav ing(B) was used to h

33、avi ng .is havi ng(C) used to have . has(D) used to havi ng .was19. I n the old society Gran dpa Zhouto work long hours a day.(A) was work ing (B) was havi ng (C) had(D) has20. Everybodyin bed.(A) has to spe nd some time(B) have to spe nd some time(C) has to spe nd sometimes(D) have to spe nd someti

34、mes2) 选择合适的词或词组填空1. I have a headache. Itake an aspiri n.(had better; would better)2. He looks sleepy. He mustbed very late last ni ght.(go; have gone)3. I want to go to the office, but youwith me.(n eed not to go; n eed not go)4. I oughtthose books to the library last week.(to have take n; to take)

35、5. The mother is telling her son,“ Youeat with your (wgeldn t; mustn t)6. He was a good swimmer so heswim to the river bank whe n the boat sank. (was able to;could)7. To travel from England to Scotland youa passport. (don t need; needn t)8. He went on foot, but heby bus.(ought have gone; should have

36、 gone)9. A: Did Ken take the job in the bookstore?B: No, but I think he.(must have; should have)10. Hetalk for hours, if you let him.(ca n; will)11. Youuse this toothbrush, it s mine, (may not; shall not)12. No matter what people say, Ido as I like.(shall; will)13. “ I m willing to let you take what

37、ever you like.” Means“ youtake whatever you like(shall; will)14. A: I haven t felt well for a week.B: Yousee a doctor.(had better; should have to)15. A: He is late,he have missed the bus?B: Yes, he must have missed the bus.(Ca n; Must)3) 单句改错(先判断句子是否正确，正确的句子不需改动。)1. Ought you smoke so much?2. If Fre

38、d didn t leave here before five, he mustn t be home yet.3. I m going home. I don t want to but I must, because my mother asked me not to go out after dark.4. After I ve finished my course, I ll can speak English fluently.5. I can be see ing the top of the tower in this bedroom.6. You are not able to

39、 play football in the park on Sun days, though you may do so on weekdays.7. He can t be working at this hour!8. Mary Blake ought to not be home by now.9. His luggage is still here, he must not have left.10. I used to writi ng poetry myself whe n I was his age.参考答案单项选择11 15 CCACB 16 20 BACCA4. to hav

40、e take n8. should have gone12. will1 5 ACCCC填空1. had better5. mustn t9. should have13. shall单句改错6 10 DDBCD2. have gone6. was able to10. will14. had better3. n eed not go7. don t need11. shall not15. Can1. (No mistake)在否定句和疑问句中，ought后面的to可省。2. mustn tea t 3. must-have to 4. can be able to5. be see ing see6. are not able to cannot 7. (No mistake)8. to not not to9. must can 10. writ ing write