高三英语情态动词考点外研版知识精讲.doc

亿库教育网 http:/www.eku.cc高三英语情态动词考点外研版【本讲教育信息】一. 教学内容：情态动词考点二. 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. shallB. willC. wouldD. 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 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 birthday.” “Will it be a great surprise to her?”A. shouldB. mustC. wouldD. shall2. You _ pay too much attention to your reading skill, as it is so important.A. cannotB. shouldntC. mustntD. neednt陷阱：几个干扰项均有可能误选。分析：最佳答案选A。cannottoo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 careful. 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, but he _ not. He likes driving his car.”A. mustB. canC. needD. 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 in the mountains last winter.” “It _ true because there was little snow there.”A. may not beB. wont beC. couldnt beD. 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 once, but I dont now.”A. may have thoughtB. can have thoughtC. may thinkD. 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 copyB. must have copiedC. should copyD. should 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 can be very unreasonable. 我父亲有时候很不讲道理。【典型例题】1. “I thought you wouldnt mind.” “Well, as a matter of fact I dont, but you _ me first.” A. should askB. should have askedC. must askD. must have asked2. “I called you yesterday. A woman answered, but I didnt recognize her voice.” “Oh, it _ my aunt Jean.”A. must beB. must have beenC. might beD. can have been3. That car nearly hit me; I _. A. might be killedB. might have been killedC. may be killedD. may been killed4. Its a very kind offer, but I really _ accept it. A. mustntB. needntC. cantD. dont 5. The police still havent found her, but theyre doing all they _. A. mayB. canC. mustD. will6. You _ practise the drums while the baby is sleeping. A. needntB. mightntC. mustntD. wont 7. You _ him the news; he knew it already. A. neednt tellB. neednt have toldC. mightnt tellD. mightnt have told8. As shes not here, I suppose she _ home.A. must goB. must have gone C. might goD. might be going9. Are you still here? You _ home hours ago. A. should goB. should have goneC. might goD. may have gone10. “I called you yesterday. A woman answered, but I didnt recognize her voice.” “Oh, it _ my aunt Jean.”A. must beB. must have beenC. might beD. can have been11. I _ have met him a long time ago. Both his name and face are very familiar.A. mayB. canC. wouldD. should13. “Shall we go shopping?” “Sorry, we _ buy anything now because none of the shops are open.”A. mustntB. needntC. cantD. shouldnt14. They often go to the restaurants for meals. They _ be very poor.A. mustntB. cantC. may notD. neednt 15. I didnt see her in the meeting room this morning. She _ have spoken at the meeting.A. mustntB. shouldnt C. needntD. couldnt17. He _ the test again, in which case, his mother will be very disappointed. A. might failB. must have failedC. should failD. could have failed18. “Why didnt she come to the meeting yesterday?” “Im not so sure. She _ ill.”A. should beB. should have beenC. must beD. might have been19. Why did you just sit and watch? You _ me.A. could helpB. should helpC. could have helpedD. must have helped20. “You _ your teacher for help. He is kind-hearted.” “Yes. A whole day _.”A. can ask, will wasteB. must have asked, had wastedC. could have asked, was wastedD. shouldnt have asked, would be wasted21. “Is there a flight to London this evening?” “There _ be. Ill phone the airport and find it out.”A. mustB. mightC. wouldD. can22. “Show me your permit, please.” “Oh, its not in my pocket. It _.”A. might fall outB. could fall outC. should have fallen outD. must have fallen out23. “Look at these tracks. It _ be a wolf.” “Dont be so sure. I think it _ be a fox.”A. must; couldB. may; mightC. need; mustD. could; need25. “Did Jim come?” “I dont know. He _ while I was out.”A. might have comeB. might comeC. mush have comeD. should have come答案与解析：1. 选B，should 后接动词完成式表示“本来应该做某事，结果未做”，此处含有责备之意。2. 选B，对过去情况的肯定推测，宜用“情态动词 + 动词完成式”，再根据句意，可确定答案为B。注：can 表示推测通常不用于肯定陈述句。3. 选B，表示过去可能发生而实际上未发生的事，用might + 动词完成式。若只是推测过去可能已经发生的事，则可用 may might + 动词完成式，如 He may might have gone. 他可能已经走了。4. 选C。由句意可知。5. 选B，do all one can 意为“尽力”或“竭尽全力”。 6. 选C，mustnt 在此相当于 cant，且语气更强。7. 选B，“neednt + 动词完成式”的意思是：本来不必做某事，但实际上做了。上句意思是“你本来不必告诉他这个消息的，因为他（当时）已经知道了”。注意，句中 knew 为过去式。8. 选B，must 后接动词完成式表示对过去情况的肯定推测，意为“一定已经做了某事”。9. 选B，should 后接动词完成式表示“本来应该做某事，结果未做”。10. 选B，对过去情况的肯定推测，宜用“情态动词 + 动词完成式”，再根据句意，可确定答案为B。注：can 表示推测通常不用于肯定句。12. 选A。may have done sth 表示对过去可能发生的事进行推测，意为“可能曾经”。13. 选C。根据上下文的语境推知。cant 意为“不能”。14. 选B。根据上下文的语境推知。cant 表推测，意为“不不能”。16. 选D。couldnt have done sth 表示对过去情况进行推测，意为“过去不可能发生过某情况”。17. 选A。根据下文的 will be 可知，“他考试再不及格”是将来的事，据此可排除B和D。再根据语意，排除C。18. 选D。从时间上看，由于是昨天没来开会，所以推测他生病也应指昨天，故排除A和C。从语境上看，既然上文说 Im not so sure，那么说明说话者对自己的推测没有很大把握，故选D。19. 选C。根据上文的过去时态可知，此句谈的是过去的事，故排除A和C。根据语境排除D。20. 选C。couldnt have done sth 结构在此表示责备，指过去本来可以做某事但实际上未做。第二空填 was wasted，陈述的是过去的一事实。21. 选B。根据下文的 Ill phone the airport and find it out 可知，说话人对自己的推测没有很大把握，故选 might。若选A，语气太强，不合语境；若选D，不合语法习惯，因为can 表推测通常不用于肯定陈述句中。22. 选D。既然“通行证现在不在口袋里”，那么它“掉出去”应发生在过去，故排除A和B。比较选项C和D所表示的意思，选D更恰当。24. 选A。根据 Dont be so sure 可知前面一空应填must。第二空填的could表示推测，虽为过去式形式，但表示现在意义，语气较委婉，它与表推测的 can 主要用于否定句和疑问句不同，它可以用于肯定陈述句。25. 选A。根据句中有关时态可知“他来”发生在过去，故排除B；根据 I dont know 可知选项C语气太肯定，不合适；选项D的意思是“本来应该来”，与语境不合。【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）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 to do the work better.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 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, you mustnt. 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”，“不准”、“不许可”或“禁止”之意，如：We must study hard and make progress every 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 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 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”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. （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 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. 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 traffic regulations. （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 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。例如：You ought to 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，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（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. / 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 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 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 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 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. 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）./ 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 a farm?/ Wouldnt you rather 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 this 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）【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 sendC. should be sending D. should send3. 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. could6. _ this book be yours? No, it _ not be mine. It _ be his.A. Can, must, may B. May, might, mustC. 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 plane, or perhaps they have been prevented from coming for some reason.A. can have missed B. may have missedC. can have lost D. may have lost9. Since the ground is white, it _ last night.A. had snowed B. must have snowedC. must be snowing D. must have been snowing10. You must be fifty, _?A. mustnt you B. neednt you C. arent you D. mnynt you11. You must have seen him off yesterday, _?A. havent you B. didnt youC. 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 him.A. mustnt B. cant C. neednt D. shouldnt14. How _ so?A. dare you to say B. dare you sayC. 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. used 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 speakingC. must be used to speakD. would be used to speaking18. I did not call to make my airline reservation （预订） but I _.A. should have 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. wouldnt C. mustnt D. shouldnt22. “Would you mind if I open the window?”“_”.A. I dont like it B. Yes .pleaseC. 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.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 s