情態(tài)動詞專題講解

1、情態(tài)助動詞專題訓練概說助動詞 (auxiliary)主要有兩類：基本助動詞(primaryauxiliary)和情態(tài)助動詞 (modal auxiliary)。基本助動詞有三個： do, have 和 be；情態(tài)助動詞有十三個：may, might;can, could;will,would; shall,should;must, need,dare,used to,ought to.上述兩類助動詞的共同特征是，在協(xié)助主動詞構(gòu)成限定動詞詞組時，具有作用詞的功能：1） 構(gòu)成否定式：He didn t go and neither did she.The meeting might not sta

2、rt until 5 o clock.2） 構(gòu)成疑問式或附加疑問式：Must you leave right now?You have been learning French for 5 years, haven3） 構(gòu)成修辭倒裝：Nowhere can he obtain any information about his sister. t you?4） 代替限定動詞詞組：A: Who can solve this crossword puzzle?B: Tom can.A: Shall I write to him?B: Yes, do.情態(tài)助動詞的特征基本助動詞與情態(tài)助動詞最主要的區(qū)

3、別之一是，基本助動詞本身沒有詞義，而情態(tài)助動詞則有自己的詞義，能表示說話人對有關(guān)動作或狀態(tài)的看法，或表示主觀設(shè)想：What have you been doing since?（構(gòu)成完成進行體，本身無詞義）I am afraid I must be going.（一定要）You may have read some account of the matter.（或許已經(jīng)）除此之外，情態(tài)助動詞還有如下詞法和句法特征：1） 除 ought 和 used 以外，其他情態(tài)動詞后面只能接不帶做是固定詞組的話，那么，所有情態(tài)動詞無一例外地只能接不帶to的不定式。如果我們把to 的不定式：ought to

4、和used to看We used to grow beautiful roses.I asked if he would come and repair my television set.2） 情態(tài)助動詞在限定動詞詞組總總是位居第一：They need not have been punished so severely.3） 情態(tài)助動詞用于第三人稱單數(shù)現(xiàn)在時的時候，沒有詞形變化，即其詞尾無-s 形式：She dare not say what she thinks.4） 情態(tài)動詞沒有非限定形式，即沒有不定式、Still, she neednt have run away.-ing分詞和 -

5、ed分詞形式：5） 情態(tài)助動詞的“時”的形式并不是時間區(qū)別的主要標志。在不少場合，情態(tài)助動詞的現(xiàn)在時和過去時形式都可以表示現(xiàn)在、過去或?qū)頃r間：Would you mind very much if I ask you to do something?She told him he ought not to have done it.6） 情態(tài)助動詞之間是相互排斥的，和 be 基本助動詞連用：即在一個限定動詞詞組中只能出現(xiàn)一個情態(tài)助動詞，但有時卻可以與haveYou should have washed the wound.Well, you shouldnt be reading a nov

6、el.現(xiàn)將情態(tài)助動詞的各種形式列表如下：肯定式否定式簡略否定式肯定式否定式簡略否定式maymay notmayn tmightmight notmightn tcancan not, cannotcan tcouldcould notcouldn twill, llwill not, ll notwon twould, dwould not, d notwouldn tshallshall notshan tshouldshould notshouldn tmustmust notmustn tneedneed notneedn tdaredare notdaren tused toused

7、not todidn t use(d) tousedn t toought toought not tooughtn t to情態(tài)助動詞的意義和用法情態(tài)助動詞從最普通的意義上來說，是修飾分句意義的一種方式，它可以反映說話者對其表述是否真實和可能的程度作出判斷。但不同的情態(tài)助動詞本身所包含的意義和用法又不同，下面逐個分析。1） can 和 could 的用法1 表示能力或客觀可能性，還可以表示請求和允許。如：Can you finish this work tonight?Man cannot live without air. Can I go now? Yes, you can.注意： co

8、uld 也可表示請求，預期委婉，主要用于疑問句，不可用于肯定句，答語應用用于現(xiàn)在時態(tài)的簡略答語中）。如：can（即could不能Could I come to see you tomorrow?Yes, you can.（否定答語可用No, I m afraid not.） can表示能力時，還可用be able to代替。如：I ll not be able to come this afternoon.2 表示驚異、懷疑、不相信的態(tài)度。（主要用在否定句、疑問句或驚嘆句中）Can this be true?How can you be so careless!This cannot be d

9、one by him.3 “ can(could) + have +過去分詞”的疑問或否定形式表示對過去發(fā)生的行為懷疑或不肯定。如：He cannot have been to that town.Can he have got the book?2）may和might的用法1 表示許可。表示請求、允許時，might比 many 的語氣更委婉一些，否定回答時要用mustn t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 .征詢對方許可在文體上比較正式，在口氣上比較

10、客氣。在日?？谡Z中，用Can I .征詢對方意見在現(xiàn)代口語中更為常見。2 用于祈使句中表示祝愿。如：May you succeed!3 表示推測、可能（疑問句不能用于此意）。He may be very busy now.4 “ may(might) + have +過去分詞”表示對過去發(fā)生的行為的推測。如：He may not have finished the work.3）must和have to的用法1 表示必須、必要。如：You must come in time.回答 must 引出的問句時，如果是否定的回答，不能用mustn t ，而要用needn t 或 don t have

11、to。Must we hand in our exercise books today?Yes, you must. (No, you don t have to.)2 “ must be +表語”的結(jié)構(gòu)表示推測，它的否定或疑問式用can 代替 must。This must be your pen.3 “ must + have +過去分詞”的結(jié)構(gòu)常用在肯定句中，表示對過去發(fā)生的行為的推測。它的否定或疑問式用 can 代替 must。He must have been to Shanghai.4 have to的含義與must 相似，兩者往往可以互換使用，但have to有各種形式，隨have

12、 的變化而定。must 與 have to有下列幾點不同：must表示的是說話人的主觀看法，而have to則往往強調(diào)客觀需要。如：The play is not interesting. I really must go now.I had to work when I was your age. must 一般只表現(xiàn)在， have 則有更多的時態(tài)形式。 二者的否定意義不大相同。如：You mustn t go.你可不要去。You don t have to go.你不必去。詢問對方的意愿時應用must。如：Must I clean all the room?4） dare和 need 的用

13、法1 need 表示“需要”或“必須” ，作情態(tài)動詞時，僅用于否定句或疑問句中，在肯定句中一般用to, ought to,或 should 代替。如：You needn t come so early.must, have Need I finish the work today? Yes, you must.注意： needn t +不定式的完成式“表示本來不必做某事而實際上做了某事”。如：You needn t have waited for me.2 Dare 作情態(tài)動詞時，主要用于疑問句、否定句和條件從句中，一般不用在肯定句中。如：How dare you say I m unfair

14、.He daren t speak English before such a crowd, dare he?3 Dare和 need 常用作實義動詞，有時態(tài)、人稱和數(shù)的變化，所不同的是，作實義動詞時，在肯定句中，dare 后面通常接帶to 的不定式，在否定和疑問句中，dare后面可接帶to或不帶to的不定式。如：I dare to swim across this river.He does not dare (to) answer.Don t you dare (to) touch it!I wondered he dare (to) say that.He needs to finish

15、 it this evening.5） shall和 should 的用法1 Shall用于第一人稱，表示征求對方的意愿。如：What shall we do this evening?2 Shall用于第一、第三人稱疑問句中，表示說話人征求對方的意見或向?qū)Ψ秸埵尽Ｈ纾篠hall we begin our lesson?When shall he be able to leave the hospital?3 Shall 用于第二、第三人稱，表示說話人給對方命令、警告、允諾或威脅。如：You shall fail if you dont work harder.（警告）He shall hav

16、e the book when I finish reading.（允諾）He shall be punished.（威脅）4 Should 表示勸告、建議、命令，其同義詞是ought to ；在疑問句中，通常用 should代替 ought to 。如：You should go to class right away.Should I open the window?Should 的含義較多，用法較活，現(xiàn)介紹三種其特殊用法。請看下面的句子：I should think it would be better to try it again.我倒是認為最好再試一試。You are mistak

17、en, I should say.依我看，你是搞錯了。I should advise you not to do that.我倒是勸你別這樣做。This is something I should have liked to ask you.這是我本來想問你的。從以上例句可以看出：情態(tài)動詞should 用于第一人稱時可以表示說話人的一種謙遜、客氣、委婉的語氣。Should 還可以用在 if 引導的條件從句， 表示一件事聽起來可能性很小，但也不是完全沒有可能。相當于 “萬一”的意思。從句謂語由should 加動詞原形構(gòu)成，主句謂語卻不一定用虛擬語氣。如：Ask her to ring me up

18、 if you should see her.你萬一見到她，請讓她給我打個電話。If you should change your mind, please let us know.萬一你改變主意，請通知我們。Should I (If I should) be free tomorrow I will come.萬一我明天有時間，我就來。此外， Why(or How) + should結(jié)構(gòu)表示說話人對某事不能理解，感到意外、驚異等意思。意為“竟會”。如：Why should you be so late today?你幾天怎么來得這么晚？ Where is Betty living? 貝蒂住在

19、哪里？ How should I know? 我怎么會知道呢？I don t know why you should think that I did it.我真不知道你憑什么認為這件事是我干的。5 “ should + have +過去分詞”結(jié)構(gòu)一般表示義務，表示應該做到而實際上沒有做到，并包含一種埋怨、責備的口氣。如：She should have finished it.I should have helped her, but I never could.You should have started earlier.6） will和 would 的用法1 表示請求、建議等，would

20、 比 will委婉客氣。如：Would you pass me the book?2 表示意志、愿望和決心。如：I will never do that again.They asked if we would do that again.3 用“ will be ”和“ will(would) + have + 過去分詞”的結(jié)構(gòu)表示推測，主要用于第二、三人稱。前者表示對目前情況的推測，后者表示對已經(jīng)完成的動作或事態(tài)的推測。如：This will be the book you want.He will have arrived by now.The guests would have arr

21、ived by that time.I thought you would have finished this by now.4 Would 可表示過去反復發(fā)生的動作或某中傾向。Would 表過去習慣時比used to 正式，并沒有“現(xiàn)已無此習慣”的含義。如：The wound would not heal.During the vacation 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 w

22、ould have told you all about it.7） ought to的用法1 Ought to表示應該。如：You ought to take care of him.2 表示推測。注意與 must 表示推測時的區(qū)別：He must be at home by now.（斷定他已到家）He ought to be home by now.（不十分肯定）This is where the oil must be.（比較直率）This is where the oil ought to be.（比較含蓄）3 “ ought to + have +過去分詞”表示過去應做某事而實際未

23、做。如：You ought to have asked him (but you didn t).這時， ought to 和 should可以互相換用。注意：在美國英語中， ought to用于否定句和疑問句時，to 可以省略。如：Ought you smoke so much?You oughtn t smoke so much.8） used to， had better， would rather的用法1 Used to表示過去的習慣動作或狀態(tài)，現(xiàn)在已不存在，在間接引語中，其形式可不變。如：He told us he used to play football when he was

24、young.在疑問句、否定句、否定疑問句或強調(diào)句中，可有兩種形式：疑問句Did you use to go to the same school as your brother?Used you to go to the same school as your brother?否定句I usedn t to go there.I didn t use to go there.Usedn t亦可拼作 usen t ，但發(fā)音皆為 ju:znt。否定疑問句Usent you to be interested in the theatre?Didn t you use to be interested

25、 in the theatre?強調(diào)句I certainly used to smoke, but it was a long time ago.I certainly did use to smoke, but it was a long time ago.其反意疑問句或簡略回答中，也有兩種形式：She used to be very fat, didn t she?（正式） / use(d)n t she?（口語）Did you use to play chess? Yes, I did.Used you to get up early in the morning? Yes, I did

26、. (Yes, I used to.)2 Had better意為“最好” ，后接不帶to 的不定式。如： We had better go now. Yes, we had (we d better / we had better).Hadn t we better stop now? (Had we better not stop now?)I think Id better be going.（用于進行時態(tài)，表“最好立即”）You had better have done that.（用于完成時態(tài)，表未完成動作）注： had best與 had better同意，但較少用。You had

27、 better 用于同輩或小輩，對長輩不可用。3 Would rather意為“寧愿” ，表選擇，后接不帶to 的不定式。如： Wouldn t you rather stay here?No, I would not. I d rather go there.由于 would rather表選擇，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 dozen cherry trees

28、than that you should tell me one lie.I d rather you didn t talk about this to anyone.（句中的 d rather不是情態(tài)動詞，would 在此是表愿望的實義動詞）練習部分一、基礎(chǔ)訓練1）單項選擇1. You _ hand it in at once, you may hand it in tomorrow.(A) neednt(B) may not(C) cant(D) must not2. That must be a mistake. No it _ a mistake.(A) must not be(B)

29、 neednt be(C) cannot be(D) would not be3. You _ go now. Its getting late.(A) had rather(B) would(C) had better(D) would4. Since the bus is crowded, we _.(A) had better walk to home(B) have better walk home(C) had better walk home(D) had better to walk home5. You _ come in now, Mary! Its getting cold

30、!“ I _ go on playing in the garden.(A) had better.had better(B) would rather.had better(C) had better.would rather(D) had better.would have better6. When I was a boy, I _ chocolate.(A) would like(B) was used to like(C) should like(D) used to like7. I wasnt supposed to go to the movies, but I _ mysel

31、f.(A) cannot help(B) couldnt but(C) had to help(D) couldnt help8. Looking at my determined face, the big boy _ pick up the fight.(A) dares not(B) dare not(C) doesnt dare(D) dares not to9. He began to write two hours ago. He _ have finished the article now.(A) must(B) ought(C) ought to(D) had to10. Y

32、ou _ to the meeting this afternoon if you have something important to do.(A) neednt to come(B) dont need come (C) dont need coming (D)neednt come11. _ you be here 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) M

33、ay(D) Can13. You _ read that article if you don t want to.”(A) neednt(B) mustn t(C) havent(D) can t14. When the storm comes all windows _.(A) ought to close (B) ought to be closing (C) ought to be closed (D) ought to closed15. I _ me what happened.(A) would like you tell(B) would like you to tell(C)

34、 would like you telling(D) would like you that you tell16. I hope you can visit my country soon, because_ to show you some of the beautiful places near my home.(A) I like(B) Id like(C) I will like(D) I shall like17. She _ for yesterdays test, but she didn t.(A)should have studied (B) would study (C)

35、 might be studying (D)must have studied18. He _ breakfast at eight oclock when he lived alone. But nowadays he _ it at seven.(A) was used to have . is having(B) was used to having .is having(C) used to have . has(D) used to having .was19. In the old society Grandpa Zhou _ to work long hours a day.(A

36、) was working(B) was having(C) had(D) has20. Everybody _ in bed.(A) has to spend some time(B) have to spend some time(C) has to spend sometimes(D) have to spend sometimes2) 選擇合適的詞或詞組填空1. I have a headache. I _ take an aspirin. (had better; would better)2. He looks sleepy. He must _ bed very late las

37、t night. (go; have gone)3. I want to go to the office, but you _ with me.(need not to go; need not go)4. I ought _ those books to the library last week. (to have taken; to take)5. The mother is telling her son,“ You _ eat with your fingers!”(wouldnt; mustn t)6. He was a good swimmer so he _ swim to

38、the river bank when the boat sank. (was able to;could)7. To travel from England to Scotland you _ a passport.(don t need; needn t)8. He went on foot, but he _ by bus. (ought have gone; should have gone)9. A: Did Ken take the job in the bookstore?B: No, but I think he _.(must have; should have)10. He

39、 _ talk for hours, if you let him. (can; will)11. You _ use this toothbrush, it s mine.(may not; shall not)12. No matter what people say, I _ do as I like. (shall; will)13.“ I m willingto letyou take whateveryou like.” Means “ you _ takewhateveryou like.”(shall; will)14. A: I haven t felt well for a

40、 week.B: You _ see 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.(Can; Must)二、強化練習1) 選擇填空1. I didnt see her in the meeting room this morning. She _ at the meeting.A. mustn t have spokenB. shouldnt have spokenC. needn t have spok

41、enD. couldn t have spoken2. One ought _ for what one hasn t done.A. not to be punishedB. to not be punishedC. to not punishedD. not be punished3. If you really want yourself to be in good health, you must _ always _ so much.A. not; be smokingB. not; have smokedC. not; to smokeD. be not; smoking4. Wi

42、th so much work on hand, you _ to see the game last night.A. mustn t go B. shouldn t go C. couldn t have gone D. shouldn t have gone5. Most of the studentsfeltratherdisappointedat the Englishparty.They say thatitorganized.A. had beenB. had to beC. must have beenD. could have been6. I m surprised tha

43、t he _ in the exam.A. should failB. would have failed C. may have failed D. should have failed7. The little girl _ there alone.A. not dare goB. dares not goC. dare not goD. dare not to go8.“ Must we do it now?” “ No, you _.”A. wontB. needn tC. can tD. dont9. He said he would rather not _ it right no

44、w.A. doingB. to doC. doD. to be doing10. You _ to the meeting this afternoon if you have something important to do.A. neednt to come B. don t need come C. dont need coming D. needn t come11. Put on more clothes. You _ be feeling cold with only a shirt on.A. canB. couldC. wouldD. must12. I _ play foo

45、tball than baseball.A. would ratherB. had betterC. like betterD. prefer13. I thought you _ like something to read, so I have brought you some books.A. mayB. mightC. couldD. must14. There was plenty of times. She _.A. mustn t have hurriedB. couldn t have hurriedC. must not hurryD. neednt have hurried

46、15. The plant is dead. I _ it more water.A. will giveB. would have givenC. must giveD. should have given16. You _ return the book now. You can keep it till next week if you like.A. cantB. mustn tC. needn tD. may not17. It s still early, you _.A. mustnt hurryB. wouldn t hurryC. may not hurryD. don t

47、have to hurry18. Please open the window, _?A. cant youB. aren t youC. do youD. will you19. We _ for her because she never came.A. mustn t have waitedB. shouldn t have waitedC. mustn t waitD. needn t wait20. May I stop here? No, you _.A. mustn tB. might notC. needn tD. won t21. It s a fine day. Lets

48、go fishing, _.A. wont weB. will weC. don t weD. shall we22. I didn t see her in the meeting room this morning. She _ at the meeting.A. mustn t have spokenB. shouldnt have spokenC. needn t have spokenD. couldnt have spoken_ better23. Please don t make a noise. _. I ll be as quiet as a mouse.A. Yes, I

49、 won tB. No, I won tC. No, I willD. Yes, I will24. The young man has made so much noisethathe _ not have been allowedto attendA. couldB. mustC. wouldD. should25. Where is John? He _ in the library.A. should beB. must beC. can beD. must have been26. Since the road is wet this morning, _ last night.A. it must rainB. it must be rainingC. it must have rainedD. it must have been rainthe concert.27. Will your brother stay home tonight? I m not quite sure. He _ to the cinema tonight.A. must goB. can goC. may goD. may be going28. She s already two hours lat