语法知识第五讲――情态动词考点

1、【 本讲教育信息参考资料】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

2、在疑问句和否定句中表示“怀疑” 、 “猜测”或“可能性” ,如:Can this green bike be Liu Dongs? (3表示“许可”时 can 可以和 may 换用,如: You can (may go home now. (4如果要表示语气婉转,可用 could 代替 can ,这时 could 不再是 can的过去式,如:Could you come again tomorrow? (5 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, 如:He will be able

3、 to do the workbetter.2. may和 might (might 为 may 的过去式的基本用法(1表示允许或征询对方许可,有“可以”之意,如:You may 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 yo

4、ur 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, youmustnt. Its too dangerous. (2 may 或 might 都可以表示可能性,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,如:They may (might be in the library now .3. must的基本用法(1 must 表示“必须” 、 “应该”之意,其否定式 must not ,缩写形式为 mustnt ,表示“不应该”

5、 ,“不准” 、 “不许可” 或 “禁止” 之意, 如:We must study hard and make progress every day. You mustnt touchthe fire. (2对以 must 提出的疑问句, 如作否定回答时,要用 neednt 或用 dont (doesnt have to (不必来回答,而不用 mustnt ,因为 mustnt 表示的是“禁止”或“不许可”之意,如: Must we finish thework tomorrow? No, you neednt (dont have to , but you must finish it in

6、 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 it be? It must be Liu Dongs.I know his father has just bought him a new one.4. can, could, may, must后接完成式的用法(1 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, Could he have said so? 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”

7、 或 “责备” 的语气。 如: When did you answer her letter? Only yesterday. Its too late. You couldhave answered it earlier, I am sure. (2 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 might , 语气就比较婉转或更加不肯定, 如:Mary might have learnedsome 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

8、the work well that day. You might have done it better. (3 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, 如:Liu Dong isnt in the classroom. He must have gone to the library.5. have to 的基本用法: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则表示客观需要,如:I must study hard. I had to give it up because of illness

9、.6. ought to的基本用法(l 表示根据某种义务或必要 “应当” 做某事, 语气比 should 强, 例如:Everyone ought to obey the trafficregulations. (2表示推测,注意与 must 表示推测时的区别: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 oilought to be. (比较含蓄 ; (3 “ ought + have+

10、过去分词” 表示过去应做某事而 实际未做。 例如:You oughtto have helped him. (but you didnt 这时, ought 与 should 可以互相换用。注意,在美国英语中 ought to 用于否定和疑问句时 to 可以省略。例如:Ought you smoke so much? You oughtnt smoke 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

11、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.8. need的基本用法 (1 need 作情态动词用时,主要用于否定句和疑问句中,如:He neednt worry about us now. (2 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 aloud every day. (3 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,

12、如: Did you answer the letter yesterday? Yes, I did. But you neednt have answered it.9. shall的基本用法(1 shall 用作情态动词时,用于第二、三人称,表示说活人的意愿,可表示“命令” 、 “警告” 、 “强 制” 、 “威胁”或“允诺”等意,如:He shall go first, whether he wants to or not. (2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

13、(1 should 作为情态动词可以表示“建议”或“劝告” ,有“应该”之意,如:You should learn from each other. (2 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 give him more help.11. will的基本用法(1 用于各人称, 可以表示 “意志” 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

14、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 可以表示一种习惯性的动作,有“总是” 或“会要”之意,如:Every morning he will have a walk along this river.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,表示说话人向对方提出请

15、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? (3 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. / Duri

16、ng 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 would have told you about it.13. used 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, 例如:He told us he used to play foot bal

17、l 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 usednt to / didnt use to go there. (usednt 也可写作 usent ; 否定疑问句:Usent you to/ Didnt you use to be interested in the theatre? 强调句:I certainly used to/ did use to smoke, but it w

18、as 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. didnt she?/ use(d nt she? Did you use to play chess? Yes, I did./ 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 now . Yes, we had (wed better/ we had better ./

19、 Hadnt we better stop now? (Had we better not stop now? / I think Id better be 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 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,例如:Id rather not say anything./ Would you rather work on afarm?/ Wouldnt you rath

20、er stay here? No, I would not. Id 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 lie./ Id rather you didnt talk about th

21、is to anyone. (句中的 d rather不是情态动词, would 在此是表愿望的实义动词情态动词考点、重难点讲解:1. “Mike is often absent from class.” “Tell him he _ answer for it if he goes on behaving like that.”A. shall B. will C. would D. can陷阱:几个干扰项均有可能误选。 分析:最佳答案选 A 。 shall 用作情态动词主要有以下两个用法:(1 用于疑问句中征求意见。如:Shall I help you? 要不要我帮帮你 ?Shall I

22、open the window? 要我把窗子打开吗?(2 用于陈述句中表示允诺、告诫、警告、威胁、命令、规定、必然性等(可用于各类人称。如: You shall suffer for this. 你会为此事吃苦头的。(表威胁Each competitor shall wear a number. 每个参赛者要戴一个号码。(表规定You shall hear everything as soon as you come. 你一来就可听到所有情况了。(表允诺请做以下试题(答案均选 shall :(1 “I promise that she _ get a nice present on her b

23、irthday.” “Will it be a great surprise to her?”A. should B. must C. would D. shall2. You _ pay too much attention to your reading skill, as it is so important.A. cannot B. shouldnt C. mustnt D. neednt陷阱:几个干扰项均有可能误选。分析:最佳答案选 A 。 cannot too 是英语中一个十分有用的表达, 意为 “不可能太, 无论怎样 也不算过分,越越”。如:You cant be too car

24、eful. 你越仔细越好。You cant praise the too much. 这本书值得大加赞扬。We cannot work too much for the people. 我们为人民做工作是不可能做过头的。A woman cannot have too many clothes. 女人买的衣服再多也不算多。注:有时也可用 can never, impossible 等与 too 连用来表示类似意思。如:It is impossible to get there too soon. 去那儿越早越好。3. “Is John coming by train?” “He should,

25、but he _ not. He likes driving his car.”A. must B. can C. need D. may陷阱:可能误选 B 或 C 。分析:最佳答案为 D 。 may 表推测, may not 意为“可能不(会坐火车来”。句中的 He should 为 He should come by train 之省略,由于其后出现转折连词 but ,说明语意有变化,再结合下文的 He likes driving his car,便可决定此题选 D 。注意,不能选 B ,因为 can 表示推测时通常不用肯定陈述句。4. “I heard they went skiing

26、in the mountains last winter.” “It _ true because there was little snow there.”A. may not be B. wont be C. couldnt be D. mustnt be陷阱:几个干扰项均有可能误选。分析:此题最佳答案为 C , 主要由下文的 because there was little snow there 这一语境所决定, 既然 “没 下什么雪”,那么“滑雪”就应是“不可能”,所以选 couldnt be,即选 C 。5. “Do you think he is lazy?” “I _ so on

27、ce, but I dont now.”A. may have thought B. can have thought C. may think D. might think答案选 A 。 从答话人的语境可知, 空格处的意思 “曾经这样想过” , 即对过去情况作推测, 故应用 “情 态动词 +动词完成式”;又因为 can 表推测不用于肯定句,故选 A 。请看类例:Their answers are exactly the same one of them _ from the other.A. must copy B. must have copied C. should copy D. sh

28、ould have copied答案选 B ,既然两人的答案完全一样,说明“抄袭”已经发生,故用“情态动词 +动词完成式”,根 据句意,应选 B 而不能选 D 。6. You _ be right, but I dont think you are.A. can B. could C. must D. should陷阱:几个干扰项均有可能误选。 分析:从语境上看, C 、 D 不宜选,在剩下的 A 和 B 中,许多同学想当然地选了 A ,认为整个句子为 现在时态,所以选 can ,而不选过去式 could ,但是最佳答案却是 B 而不是 A 。按照英语语法,情态动词 can 用于推测表示可能性

29、时, 通常只用于否定句或疑问句中, 而不用于肯定句中; 但 could 用于表推测时, 却不仅可用于否定句和疑问句,也可用于肯定句,且此时的 could 并不是 can 的过去式,与 can 也没有 时间上的差别,只是 could 比 can 语气更委婉,所以答案选 B 。注:can 在以下特殊情况下,也可用于肯 定句。一是表示抽象的可能性,即从理论上或逻辑上分析是可能的,但是实际上未必会发生。如:Anyone can make mistakes. 任何人都可能会犯错误。二是后接“ be (get, seem, become+形容词”,表示“有时 会”、“时常会”等。如:My father c

30、an be very unreasonable. 我父亲有时候很不讲道理。 【模拟试题】1. If they _ to do this work, he might do it some other way.A. were B. should C. will D. can2. I was told yesterday that the company _ me to Rome next week for a business conference.A. should have sent B. were going to send C. should be sending D. should s

31、end3. Lets take a walk, _? A. will we B. dont we C. do we D. shall we4. He was a good swimmer so he _ swim to the river bank when the boat sank.A. could B. might C. should D. was able to5. I went to the doctors yesterday, I had to wait for half an hour before he _ see me.A. can B. may C. might D. co

32、uld6. _ this book be yours? No, it _ not be mine. It _ be his.A. Can, must, may B. May, might, must C. Can, may, must D. Must, can, may7. “We didnt see him at the lecture yesterday.” “He _ it.”A. mustnt attend B. cant have attended C. would have not attended D. needed have attended8. They _ the plan

33、e, or perhaps they have been prevented from coming for some reason.A. can have missed B. may have missed C. can have lost D. may have lost9. Since the ground is white, it _ last night.A. had snowed B. must have snowed C. must be snowing D. must have been snowing10. You must be fifty, _? A. mustnt yo

34、u B. neednt you C. arent you D. maynt you11. You must have seen him off yesterday, _?A. havent you B. didnt you C. mustnt you D. neednt you12. That must be a mistake. No .it _ be.A. cant B. isnt able to C. can D. was able to13. He had known the matter before you told him, so you _ have told it to hi

35、m.A. mustnt B. cant C. neednt D. shouldnt14. How _ so? A. dare you to say B. dare you say C. do you dare say D. dare to say15. You are their teacher. You _ care of them.A. should to take B. might to take C. ought to take D. need to take16. She is studying medical science now but she _ a lawyer.A. us

36、ed to be B. would be C. were D. had been17. If you were in an English-speaking country, you, too, _ English every day.A. will be used to speak B. will be used to speaking C. must be used to speak D. would be used to speaking18. I did not call to make my airline reservation (预订 but I _.A. should have

37、 B. may have C. must have D. shall have19. As a girl, she _ get up at six every day.A. would B. will C. might D. should20. Dont you remember that we _ to the cinema tonight?A. would go B. go C. are going D. will be gone21. Shall I tell John about it? No, you _. Ive told him already.A. neednt B. woul

38、dnt C. mustnt D. shouldnt 22. “Would you mind if I open the window?” “_”.A. I dont like it B. Yes .please C. No, please D. No. Im sorry23. “Would you tell me something about the affair?” “_”.A. Yes .please B. All right C. Not at all D. I do24. M: _? T : Id love to, but Im afraid I have no time."

39、;M :0h, no. Youll surely come over. T : Its very nice of you. But Im sorry I have to go to a meeting.A . Do you have lunch out in a restaurant B. Shall I have you with me at my birthdayC. Did you go to see the film D. Have you enjoyed yourself at the party25. “You ought to have come here ten minutes

40、 ago?” “Yes, I _.”A. ought to B. ought to have C. ought D. have ought to26. “Would you like to go out for a walk?” “Yes, _.”A. Id like to B. Id like C. Ill like to D. I would27. _ you succeed ! A. Can B. May C. Must D. Will28. Did he need _ then? A. leave B. to leave C. leaving D. left29. Do you thi

41、nk if he dares _ in public.A. speak B. speaking C. to speak D. spoken30. He _ eating American food since he came here.A. used to B. has been used C. has been used to D. was used to31. A computer _ think for itself; it _ be told what to do.A. may not, must B. mustnt, might C. shouldnt, could D. cant,

42、 must32. “_ you mind my opening the window?” “Not at all.”A. Shall B. Should C. Will D. Would33.1 didnt hear the phone. I _ asleep.A. must be B. must have been C. should have been D. could have been34. You _ me about it earlier, but you didnt.A. should have told B. would have told C. must have told

43、D. should tell35. The teacher told the students that they _ keep silent in class all the time.A. ought to not B. ought not to C. ought not to have D. cant36. “May I go now?” “No, you _.” A. mustnt B. neednt C. mightnt D. wont37. You _ do the exercise if you dont want to.A. may not B. cant C. mustnt

44、D. neednt38. You _ pay more attention to your spelling next time.A. would B. should C. will D. shall39. The girl _ out alone at night.A. dare not go B. dare not to go C. dares not go D. does not dare go40. There _ be a lot of small houses on both sides of the street.A. used to B. get used to C. woul

45、d D. did use to【模拟试题】 一. 单项选择 1. Australia _to have been connected to South America millions of years ago. A. is believed B. believes C. believed D. is believing 2. If youre driving there, I wonder if you can give me a _. A. hand B. seat C. drive D. lift 3. With his mother _ him, he is getting on we

46、ll with his work. A. help B. to help C. helping D. helps 4. I have moved into a much bigger place. So next time you come here, I can find you _ bed in my flat. Oh, thats wonderful. Then I wont go to _ hotel. A. the; a B. the; 不填 C. a; the D. a; 不填 5. However bad the situation is, the fact should not

47、 _ the people who are most concerned. A. be kept up B. be kept from C. be kept on D. be kept in with 6. This school was the first _ textbooks as well as reading materials. A. publishing B. to publish C. having published D. published 7. I passed by the sports field the other day, _ there was a footba

48、ll match going on then. A. that B. where C. which D. when 8. -It was a great party, thank you. -But Jill, why _ you _ more friends to come? A. haventinvited B. dont invite C. didnt invite D. wont invite 9. _ was expected, only five people turned up at the party, _disappointed the hostess very much.

49、A. As; which B. As; that C. It; that D. It; which 10. The music, digitally _ in the studio, sounded fantastic at the party last night. A. recorded B. recording C. to be recorded D. having recorded 11. What are you doing, John? Why stop? To be on the safe side, wed fill up the tank now for we _ run o

50、ut of gas on the way. A. must B. will C. might D. should 12. _ at the office, Mr. Green found the papers prepared for his boss were left at home. A. To arrive B. On arriving C. As arriving D. While arrived 13. He sent his friend a gift, _ to make her feel better. A. hoped B. hoping C. to hope D. hop

51、e 14. Have you finished your homework, Mary? No, I _ my mother in the kitchen all day yesterday. A. would help B. had helped C. was helping D. used to help 15. The moment Jenny got home, she noticed a woman waiting for her. She _ her before. A. never saw B. had never seen C. never sees D. has never

52、seen 二. 完形填空 One evening, sitting at the window sewing, my mother called me, “Come here, ”she said. “ 16 . ”She held my head against her 17 , and after a puzzled moment I felt a 18 foot drumming on my cheek. “You see ? ”she said, “Its alive. You can 19 it, cant you?” I accepted it, as I accepted eve

53、rything, without 20 . It was as good a place for the baby to be as any other and I never 21 about why it got in nor how it would finally get out. A baby would come? I 22 noticed. That there were soon to be 23 of us would not make any difference to me. I had my place, star-like in my small universe.

54、24 , certainly not a baby, could 25 that. I was 26 , however. I soon found that things had 27 a great deal. I had never been the 28 . Now I was no longer the youngest. I was simply the one in the 29 . My sister had certain 30 because 6 she was the oldest, and my brother was the baby, the son, the mu

55、ch 31 boy. More than that, he had all sorts of things that never came to me. As he grew, it became 32 that my brother had been the center of everything. People smiled when they saw him. He made them happy 33 by being there. And he had the sort of childish beauty that always turns heads and draws a s

56、econd 34 . He was so charming that he was immediately loveable. Later he also turned out to be 35 , although perhaps not quite as clever as I was. 16. A. Look B. See C. Listen D. Stop 17. A. stomach B. back C. side D. shoulder 18. A. strong B. hard C. soft D. tiny 19. A. believe B. feel C. notice D. touch 20. A. surprise B. delay C. trouble D. effort 21. A. worried B. argued C. regretted D. doubted 22. A. hardly B. certainly C. possibly D. willingly 23. A. two B. three C. four D. five 24. A. Anything B. Something C. Nothing D. Everything 25. A. improve B. threaten C.