二轮复习——情态动词.doc

1、二轮专题复习整理情态动词情态动词是一种本身有一定的词义，表示说话人的情绪、态度或语气的动词，但它不能单独作谓语，只能和其他动词一起构成谓语。情态动词有can (could), may (might), must, have to, shall(should, will (would), dare (dared), need (needed), ought to等。 情态动词无人称和数的变化；不能单独使用，必须与其后的动词原形构成谓语。一、can, could1) 表示能力（体力、知识、技能）。Can you lift this heavy box? （体力）Mary can speak thr

2、ee languages.（技能）How can you know it?( 知识）此时可用be able to 代替。 Can 只有一般现在时和一般过去式；而be able to 则有更多的时态。I ll not be able to come this afternoon.当表示 “经过努力才得以做成功某事”时应用 be able to，不能用Can。如：He was able to go to the party yesterday evening in spite of the heavy rain.2) 表示请求和允许。-Can I go now?- Yes, you can. /

3、No, you cant.此时可与may互换。在疑问句中还可用could,might代替，不是过去式，只是语气更委婉，不能用于肯定句和答语中。- Could I come to see you tomorrow?- Yes, you can. ( No, Im afraid not. )3) 表示客观可能性（客观原因形成的能力）。Theyve changed the timetable, so we can go by bus instead.This hall can hold 500 people at least.4) 表示推测（惊讶、怀疑、不相信的态度），用于疑问句、否定句和感叹句中。

4、Can this be true?This cant be done by him.How can this be true?二、may, might1) 表示请求和允许。might 比 may 语气更委婉，而不是过去式。否定回答时可用cant或 mustnt，表示 “不可以，禁止”。-Might/ May I smoke in this room?- No, you mustn t.- May/Might I take this book out of the room?- Yes, you can. (No, you cant / mustnt. )用 May I. ？征徇对方许可时比较正

5、式和客气，而用Can I. ？在口语中更常见。2）用于祈使句，表示祝愿。May you succeed!3) 表示推测、可能性（不用于疑问句）。might 不是过去式，它所表示的可能性比may 小。1 He may /might be very busy now.2 Your mother may /might not know the truth.三、must, have to1) 表示必须、必要。You must come in time.在回答引出的问句时，如果是否定的， 不能用 mustnt（禁止， 不准），而用 neednt, don t have（不to必） .- Must we

6、hand in our exercise books today?- Yes, you must.- No, you don t have to / you needn t.2) must是说话人的主观看法，而have to则强调客观需要。Must只有一般现在时，have to有更多的时态形式。1 he play isnt interesting, I really must go now.2 I had to work when I was your age.3) 表示推测、可能性（只用于肯定的陈述句）1 You re Tom s good friend, so you must knoww

7、hat he likes best.2Your mother must be waiting for you now.四、dare, need1) dare 作情态动词用时, 常用于疑问句、否定句和条件从句中, 过去式形式为dared。1 How dare you say Im unfair?2 He daren t speak English before such a crowd, dare he?3 If we dared not go there that day ， we couldn t get the beautiful flowers.2) need 作情态动词用时, 常用于疑

8、问句、 否定句。在肯定句中一般用must, have to, ought to, should代 替。1You neednt come so early.2. - Need I finish the work today?- Yes, you must. / No, you neednt.3) dare 和need 作实义动词用时，有人称、时态和数的变化。在肯定句中，dare 后面常接带to 的不定式。在疑问句和否定句中，dare 后面可接带to 或不带to的不定式。而need 后面只能接带to 的不定式。1. I dare to swim across this river.2. He do

9、esn3. He needs to finish his homework today. t dare (to) answer.五、shall, should1) shall 用于第一人称，征求对方的意见。What shall we do this evening?2) shall 用于第二、三人称，表示说话人给对方的命令、警告、允诺或威胁。1.You shall fail if you dont work警hard告).(2.He shall have the book when I finish it.( 允诺 )3. He shall be punished.( 威胁 )六、will,

10、would1) 表示请求、建议等， would 更委婉。Will / Would you pass me the ball, please?2) 表示意志、愿望和决心。1. I will never do that again.2. They asked him if he would go abroad.3) would表示过去反复发生的动作或某种倾向。would表示过去习惯时比used to 正式，且没有 “现已无此习惯 ”的含义。1. During the vacation, he would visit me every other day.2. The wound would not

11、 heal.4) 表示估计和猜想。It would be about ten oclock when she left home.七、should, ought to1) should, ought to 表示 “应该 ”， ought to 表示义务或责任，比should 语气重。1.I should help her because she is in trouble.2. You ought to take care of the baby.2)表示劝告、建议和命令。 should, ought to 可通用，但在疑问句中常用should。1.You should / ought to

12、go to class right away.2. Should I open the window?3)表示推测should , ought to ( 客观推测 ), must(主观推测 )。1.He must be home by now. ( 断定他已到家 )2.He ought to/should be home by now.( 不太肯定 )3.This is where the oil must be.( 直爽 )4. This is where the oil ought to/should be.( 含蓄 )八、情态动词 +不定式完成式（have done）1) can / c

13、ould + have done 在肯定句中表示 “本来可以做而实际上能做某事 ”，是虚拟语气；在疑问句或否定句中表示对过去行为的怀疑或不肯定, 表示推测。1.You could have do ne better, but you didnt try your best（虚.拟语气）2.He can t have been to that town（.推测）3. Can he have got the book?（推测）2) may / might + 不定式完成式（ have done）表示对过去行为的推测。 不能用于疑问句中，没有虚拟语气的用法。 Might 所表示的可能性比may 小。

14、1.He may not have finished the work .2. If we had taken the other road, we might have arrived earlier.3） must +不定式完成式（have done）用于肯定句中，表示对过去行为的推测。意为“一定、想必 ”。其疑问、否定形式用can， cant代替。can / could + have done 表示过去可能做了某事。1. You must have seen the film Titanic.2. He must have been to Shanghai.4） should +不定式完

15、成式（have done）用于肯定句中，表示对过去行为的推测。He should have finished the work by now 。表示 “本应该做而实际上没有做某事”，其否定式表示某种行为本不该发生却发生了。可以与 ought to +不定式完成式（have done）互换。1. You ought to / should have helpe d him. (but you didn t.)2. She shouldn t have taken away my measuring tape, for I wanted to use it.5) needn t不+定式完成式（ h

16、ave done）表示 “本来不必做而实际上做了某事 ”。You neednt have watered the flowers, for it is going to rain.6) will + 不定式完成式（ have done）主要用于第二、三人称，表示对已完成的动作或事态的推测。He will have arrived by now.高考考题衔接：1.(2010全国 I29) Just be patient. Youexpect the world to change so soon.A. cantB. needn tC. may notD. will not2.(2010全国 II

17、17) I m afraid Mr. Harding _ see you now . he s busy.A. can tB. mustn tC. shouldn tD. needn t3.(2010北京23) Good morning. I ve got an appointment with Miss Smith in the Personnel Department.- Ah, good morning. You _ be Mrs. Peters.A. mightB. mustC. wouldD. can4.(2010上海 29) -Sorry, Professor Smith. I d

18、idnt finish the assignment yesterday.-Oh, youhave done it as yesterday was the deadline.A. mustB. mustntC. shouldD. shouldnt5.(2011全国 I32) They_ have arrived at lunchtime but their fight was delayed.A. willB. canC. mustD. should6.(2011全国 II8) If yousmoke， please go outside.A. canB. shouldC. mustD. m

19、ay7.（ 2011 年北京24） I don t really like James. Why did you invite him? Don t worry. Hecome. He said he wasn t certain what his plans were.A must notB need notCwould notD might not8.(2011上海 28)I _ worry about my weekend I always have my plans ready before it comes.A. cantB. mustn tC. daren tD. needn t9

20、.(2012全国 I23) I_ thank you too much for all your help to my son while we were away from home.A. won tB. can tC. canD. will10.(2012 全国 II14)Did you ask Sophia for help? Ineed to - I managed perfectly well on my own.A. wouldntB. dontC. didntD. wont11.(2012 全国 II17) Im going to Europe on vacation together with John if Ifind the money.A. canB. mightC. wouldD. need12.(2012北京33) We _ the difficulty together, but why didn t you tell me?A. should faceB. might faceC. could have facedD. must have faced13.(2012上海 28)The new law states that people _ drive after drinking alcohol.A. woul