高三英语语法复习教案之情态动词.doc

高三英语语法复习教案之情态动词
一．情态动词的语法特征
1. 情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。
2. 情态动词 除ought 和have 外，后面只能接不带to 的不定式。
3. 情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。
4. 情态动词没有非谓语形式，即没有不定式、分词、等形式。
情态动词的分类和意义
意义情态动词
can, may, might, could, would, will, shall, must, should, ought to, used to
二．情态动词的基本用法
1. can (could)
1) 表示能力，could主要指过去时间。例如：
① Two eyes can see more than one.   两只眼比一只眼看得清。
② Could the girl read before she went to school?   这女孩上学前能识字吗？
2) 表示可能（理论上或是逻辑判断上）。例如：~,>_K
① He can’t (couldn’t) have enough money for a new car.  他不可能有足够的钱买新车。
② You mustn’t smoke while you’re walking around in the wood. You could start a fire.  在林子里走时勿吸烟，那样可能会引起火灾。
3) 表示允许。例如：
① Can I have a look at your new pen?   我可以看一看你的新钢笔吗？
② He asked whether he could take the book out of the reading—room.  他问他可不可以把书带出阅览室。
4) 表惊异、怀疑、不相信等态度。主要用于否定句、疑问句或感叹句中。例如：
① Where can (could) they have gone to?   他们会去哪儿了呢？
② How can you be so careless?   你怎么这么粗心？
5) 比较委婉客气地提出问题或陈述看法。例如：
① Can (Could) you lend me a hand?   帮我一把好吗？.
② I’m afraid we couldn’t give you an answer today.  恐怕我们今天不能给你答复。
2．may (might)
1) 表允许，might可以指过去时间，也可指现在时间，语气更委婉。例如：
① You may take whatever you like.你喜欢什么就拿什么。
② May (Might) I ask for a photo of your baby? 我可以要一张你宝宝的照片吗？
在回答以may引起的问句时，多避免用这个词，而用其它方式，如Yes, please. / Certainly. / Please don’t. / You’d better not. / No, you mustn’t.等，以免显得太严峻或不客气。
2) 表可能（事实上）。可以指过去时间，也可以指现在时间，但语气更加不肯定。例如：
① He may be at home.   他可能在家。\
② She may not know about it.   她可能不知道这件事。
must
1) 表示义务。意为“必须”（主观意志）。例如：
① We must do everything step by step.   我们一切都必须循序渐进地做。
② --Must we hand in our exercise books now?我们现在就要交练习本吗？
--No, you needn’t. / No, you don’t have to.   不必。
4) 表示揣测。意为“想必、准是、一定”等，只用于肯定句。例如：
① He must be ill. He looks so pale.   他准是病了。他的脸色苍白。
② She’s wearing a diamond necklace. She must have a lot of money. 她戴着钻石项链，一定很有钱。:
3．shall
1) 表征询意见，用于第一、第三人称疑问句。例如：
① Shall I get you some tea?   我给你点茶好吗？
② Shall the boy wait outside?  让那男孩在外面等吗？
2) 表说话人的意愿，有“命令、允诺、警告、决心”等意思，用于第二、第三人称陈述句。例如：
① You shall do as I say. 按我说的做。（命令）
② You shall have my answer tomorrow. 你明天可以得到我的答复。（允诺）
③ He shall be sorry for it one day, I tell you. 有一天他会后悔的，我告诉你。（警告）
④ Nothing shall stop us from carrying out the plan. 什么也不能阻止我们执行这项计划。（决心）
4．will
1) 表意愿，用于各种人称陈述句。例如：
① I will do anything for you.   我愿为你做任何事。
② None is so blind as those who won’t see.   不愿看的人眼最瞎。
③ If you will read the book, I’ll lend it to you.  如果你愿意读这本书，我会把它借给你。
2) 表请求，用于疑问句。例如：
① Will you close the window?   请你把窗户关上好吗？
② Won’t you drink some more coffee?   再来一点咖啡好吗？
3) 表示某种倾向或习惯性动作。例如：
① Fish will die out of water.   鱼离开水就不能活。
② The door won’t open.  这门打不开。
5. should
1) 表义务。意为“应该”（某件事宜于做），用于各种人称。例如：
① You should be polite to your teachers.   你对老师应该有礼貌。
② You shouldn’t waste any time.   你不应该浪费时间。
2) 表推测，意为“想必一定、照说应该、估计”等。例如：
① The film should be very good as it is starring first-class actors.  这部新电影是一流演员主演的，估计拍得很好。
② They should be home by now.   照说他们现在应当已经到家了。
3)（表示不确定）万一。例如：
① If I should see him, I'll tell him. 万一我见到他，我就告诉他。
② If it should rain tomorrow, the sports meeting would be postponed. 万一明天下雨,比赛就延期举行。"
6.  would
1) 表意愿。例如：:
① They would not let him in because he was poorly dressed. 他们不让他进去因为他衣着破旧。
② I said I would do anything for you.   我说过我愿意为你做任何事。
2) 表委婉地提出请求、建议或看法。例如：
① Would you mind cleaning the window?   请把窗户擦一下好吗？
② They wouldn’t have anything against it.   他们不会有什么反对意见。
3) 表过去反复发生的动作或过去的一种倾向。例如：:
Every time she was in trouble, she would go to him for help.   她每遇到麻烦都会向她求助。他告诉我盒子打不开了。
7.ought to
1) 表义务，意为“应该”（因责任、义务等该做），口气比should稍重。例如：
① You are his father. You ought to take care of him.你是他父亲，应当管他。
② You oughtn’t to smoke so much.   你不应该抽这么多烟。
2) 表推测，暗含很大的可能，语气较弱。例如：
① Han Mei ought to know his telephone number. 韩梅该知道他的电话号码。
② There’s a fine sunset; it ought to be a fine day tomorrow.  今天有晚霞，明天应该是个好天。
8. used to
表示过去的习惯动作或状态，现在不复发生或存在。疑问式和否定式有两种。例如：i
① There used to be a building at the street corner, but it has been pulled down.   街道拐角处过去有座楼房，现在拆了。
② I usedn’t (didn’t use) to smoke.   我过去不抽烟。j }F
③ Used you (Did you use) to go to school on foot? 你过去常步行去学校吗？
9.特殊情态动词need和dare的用法：
need和dare既可用作情态动词，也可用作实义动词。用作情态动词时，主要用于否定句和疑问句。用作实义动词时，可用于各种句式。
1) 用作情态动词。例如：|
① You needn’t telephone him now.   你现在不必打电话给他。
② I don’t think you need worry.   我想你不必发愁。
③ She dare not go out alone at night.   她晚上不敢一个人出去。
④ How dare you say I’m unfair?   你竟敢说我不公平？_
2) 用作实义动词。例如：
① You don’t need to do it yourself.   你不必亲自做这件事。
② We need to tell them the news.   我们需要把这消息告诉他们。
③ The table needs painting (to be painted.).   桌子需要油漆一下。
④ We should dare to give our own opinion.   我们要敢于提出自己的观点。
⑤ He did not dare (to) look up.   他不敢抬头看。
⑥ I dare say he’ll come again.   我想他会再来的。
【注意】（I dare say…为固定习语）
◆ 难点突破
1. 情态动词后跟完成式和进行式的用法
1) 情态动词+动词完成式
情态动词+动词完成式即“情态动词+ have + done分词”，表示对过去行为或动作进行推测、评论或判断。
must have done 表示对过去某事的肯定猜测。其否定或疑问形式都用can(could) 来表示。  例如：  
① Since the road is wet, it must have rained last night.
② He can’t have missed the way. I drew him a map.
③ The dictionary has disappeared. Who could have taken it?
当然对现在发生或将来发生的事情,要用must do 表示猜测, 否定为can’t do。例如：
④ He must understand that we mean business.
⑤ You must be hungry after a long walk.
may / might have done表示推测过去某事“也许”发生了.may 比 might 表示的可能性在说话人看来稍大些。例如：
⑥ I can’t find my keys. I may / might have left them at the school yesterday.
could have done 在肯定句型中, 往往用作委婉的批评. 本应该做什么,而没做; 有时也用作猜测。例如：
⑦ You could have told us earlier.
⑧ Tom could have taken the dictionary.
ought to / should have done和 ought not to / shouldn’t have done用于对已发生的情况表示“责备”、“不满”，分别表示“本应该…”和“本不应该…”。例如：
⑨ With all the work finished, I should have gone to the party last night.
⑩ You ought not to have made fun of him. He is not the one you laugh at but learn from.
needn’t have done 表示过去做了某事，但没有做的必要， 意为“本没必要…”。例如：
⑾ You needn’t have waken me up; I don’t have to go to work today.
【注意】表示推测过去某动作发生的可能性时，就表示的可能性程度而言，must最大，could其次，may更次之，might最小。例如：
    ⑿ ---I wonder how Tom knew about your past.  
---He must / could / may / might have heard of it from Mary.
2) 情态动词+动词进行式
情态动词+行为动词进行式（即情态动词+ be + doing形式），表示推测或评论某动作现在是否正在进行。例如：
① He must be playing basketball in the room.
② She may be staying at home.
3) 情态动词+动词完成进行式
情态动词+行为动词完成进行式（即情态动词+ have been + v-ing形式），表示推测或评论过去某动作是否正在进行或一直在进行。例如：
① They should have been meeting to discuss the problem.
② He may / might have been buying stamps in the post office when you saw him.|
三、几组词的辨异
1. can 和be able to
1）情态动词can只有两种时态形式，现在式can和过去式could，而be able to有多种时态形式
Mary can play the piano. She has been able to play it since she was 5.
玛丽会弹钢琴。她五岁起就会弹了。
2）用在过去时中，could经常表示能够做某事，事实上不一定去做，而was / were able to则表示“过去做成了某事”。在否定句中两者可通用。
He could swim across the English Channel. But he didn’t feel like it that day.
他能游过英吉利海峡，但那天他不想游。
Yesterday I was able to get home before the heavy rain.   昨天我在下大雨前赶到了家里。
2. must和 have to语法学习纲要由江苏省靖江高级中学外语组为英语猫网站特供
must表示主观意志，而have to表示由于客观因素不得不做某事。must没有过去式，除在间接引语中可用于表示过去时间，在直接引语中表示过去时间应该用had to代替。
I told her that she must give up smoking.  我叫她必须戒烟。
We had to get everything ready that night.  我们那晚得把一切准备就绪。"
3. would和used to
1）used to表示过去与现在或过去某时与后来的情况有不同，而would只表过去的情况。
People used to think that the earth was flat.
过去人们认为地球是平的。（现在人们不这么认为。）
She would go out for a walk in the morning when she was in the country.
在乡下时，她总是在早晨去散会儿步。（可能现在仍有散步的习惯。）
2）used to可表示过去的习惯动作和经常的情况，而would只表示过去的习惯动作。
He used to ∕would smoke while writing.   过去他写东西时常抽烟。
She used to be fat.   她过去很胖。
◆ 考题剖析
例题1. I didn't hear the phone. I ________ asleep. (NMET 89)
A. must be     B. must have been       C. should be     D. should have been;
答案 B  从原题中的I didn't hear the phone．这一信息可以判断出，用must have
done表示对过去事实的准确的肯定猜测。
例题2. Tom ought not to             me your secret ,but he meant no harm. (NMET93)
　         A. have told     B. tell      C. be telling      D. having told
答案 A   该句意思是：“汤姆本来不该告诉我你的秘密，但他没有伤害你的意思。”
例题3. I was really anxious about you. you    home without a word. (NMET2001)
A. mustn't leave             B. shouldn't have left
C. couldn't have left        D. needn't leave.
答案 B  shouldn't have done为不该做了某事。
例题4. ---Could I borrow your umbrella, please?
       ---I’m afraid you _______.
      A. could         B. can      C. couldn’t        D. can’t
答案 D  此题极易错选C。其实could在问句中表示请求，为了语气的委婉和客气才用过去式，而答句必须按照实际情况回答，故选can’t，以求和I’m afraid（在此表示婉拒）一致。
例题5. ---Don't forget to come to my birthday party tomorrow.
　      ---______.`
　A. I don't　 B.　I won't　 C. I can't　D. I haven't
答案 B　 will既可当作情态动词，表请求、建议、也可作为实义动词表"意愿、意志、决心"，本题表示决心，故选B。
例题6. ----Shall we go skating or stay at home?
----Which ___ do?
A. do you rather　　B. would you rather　 C. will you rather　 D. should you rather
答案 B   本题考查情态动词would rather的用法，would rather +do sth 意为“宁愿”，本题为疑问句，would 提前，所以选B。
◆思考
几组情态动词的辨异
1. can 和be able to
情态动词can只有两种时态形式，现在式can和过去式could，而be able to有多种时态形式。例如：
① Mary can play the piano. She has been able to play it since she was 5.   玛丽会弹钢琴。她五岁起就会弹了。
用在过去时中，could经常表示能够做某事，事实上不一定去做，而was / were able to则表示“过去做成了某事”。在否定句中两者可通用。例如：
② He could swim across the English Channel. But he didn’t feel like it that day.  他能游过英吉利海峡，但那天他不想游。
③ Yesterday I was able to get home before the heavy rain.   昨天我在下大雨前赶到了家里。
2. must和 have to
must 和 have to 都可以表示“必须”，但有几点区别：
must 强调“内在的职责”、“义务”，而have to 强调“外界压力”、“不得已而为之”。^
have to可用于多种时态，而must一般用于现在时，其过去时与将来时分别由had to与shall / will have to代替。
在回答must引起的问题时，如果是否定的答复，不能用mustn’t，而要用needn’t或don’t have to，因为mustn’t是“一定不要”、“一定不能”的意思。例如：
① You must come to the classroom before eight.  八点前你必须来教室。
② It is raining hard outside, but I have to leave now.  虽然外面下着大雨，可我还是得走了。
③ ---Must we do it now?    我们必须现在做吗？
---No, you needn’t.   不，不必。
3. would和used to
used to表示过去与现在或过去某时与后来的情况有不同，而would只表过去的情况。例如：
① People used to think that the earth was flat.过去人们认为地球是平的。（现在人们不这么认为。）
② She would go out for a walk in the morning when she was in the country.
在乡下时，她总是在早晨去散会儿步。（可能现在仍有散步的习惯。）
used to可表示过去的习惯动作和经常的情况，而would只表示过去的习惯动作。例如：
① He used to ∕would smoke while writing.   过去他写东西时常抽烟。
② She used to be fat.   她过去很胖。
4. can 和 may
考试中主要测试can，may或could，might表示可能性的区别及对may构成的疑问句的回答
can, could, may, might都可以表示可能性.can could表示潜在的可能性或理论上或逻辑判断上存在的可能性；而may, might则表示事实上的可能性。此外，can还具有“有能力”的意思，而may与might则不具此意。例如：^
① According to the weather forecast, it may rain tomorrow.   据气象预报，明天可能下雨。
② Any man with a little sense can see that he is wrong.   任何一位有头脑的人都能看出他错了。
May I / we …？这一类疑问句的肯定回答为Yes, please.或Certainly；否定回答为Please don’t.或No, you mustn’t. 例如：
   ③ ---May we leave now?    我们可以走了吗？
---No, you mustn’t. You haven’t finished your home work yet.   不行，你们还没完成工作呢。
5. used to +do, be used to +doing和be used to +do
used to +v意为“过去常常”，“过去一直”；be used to +v-ing /  n（名词）意为“习惯于”；be used to +v意为“被用来（做某事）”。
used to只表示过去，而be used to +v-ing / n可表示现在、过去或将来。例如：
① He used to smoke. Now he doesn’t.   他过去吸烟，现在不吸了。
② He’s quite used to hard work / working hard.   他习惯于埋头苦干。
③ The knife is used to cut bread.   这把刀是用来切面包的。
6. 用作情态动词的其他短语
would rather, would sooner, would (just) as soon, had rather, had better, had sooner, can not but, may  (just) as well等可用作情态动词。例如：
① The soldier would sooner die than surrender.   那士兵宁死不屈。
② I’d rather walk than take a bus.    我宁愿步行也不愿乘车。
③ If you don’t like to swim, you may just as well stay at home.   如果你不想游泳，你也可以呆在家里。
【注意】这些短语后一般直接跟动词原形.would (had) rather, would (had) sooner, would (just) as soon后可跟that 引导的从句，that常省去，从句要用虚拟语气。对现在和将来的假设用过去时，对过去的假设用过去完成时。例如
① I would rather you came on Sunday.   我宁可你星期天来。
② I would sooner he hadn’t asked   但愿他没问。
7. would rather表示"宁愿"
would rather do
would rather not do
would rather… than…　 宁愿……而不愿。
还有would sooner, had rather, had sooner都表示"宁愿"、"宁可"的意思。例如：
   ① If I have a choice, I had sooner not continue my studies at this school.
　 ② I would rather stay here than go home.    我宁可呆在这儿也不愿回家。
= I would stay here rather than go home. 
⑻  情态动词的回答方式
问句　　　      肯定回答　　　　否定回答
Need you…?　　Yes, I must.　　　No, I needn't/don't have to.
Must you…?　　　　　　　　　　　
典型例题
① ---Could I borrow your dictionary?
　 ---Yes, of course, you____.　
　 A. might　B. will　 C. can　 D. should
答案C。 could表示语气的委婉，并不表示时态。答语中的of course，表示语气的肯定，允许某人做某事时，用can和 may来表达，不能用could或might。
【注意】 will 与you连用，用来提出要求或下命令。should与you 连用，用来提出劝告。
② ---Shall I tell John about it?
　 ---No, you ___. I've told him already.
　 A. needn't　　B. wouldn't　　C. mustn't　　D. shouldn't
答案A。needn't 不必，不用。 wouldn't 将不, 不会的。 mustn't 禁止、不能。 shouldn't　不应该。本题为不需要，不必的意思，应用needn't。

情态动词基础训练
1. ---Shall I tell John about it?
---No, you ______. I’ve told him already.
A. needn’t        B. wouldn’t       C. mustn’t      D. shouldn’t
2. ---There were already five people in the car, but managed to take me as well.5Fr
  ---It ______ a comfortable journey.
  A. can’t be    B. shouldn’t be C. mustn’t have been    D. couldn’t have been
3. ---Why didn’t you come to see me?
  ---I ______, but I was too busy yesterday.
  A. like to         B. should like to C. would like to have        D. am going to
4. You can’t imagine that a well-behaved gentleman ______ be so rude to a lady.
  A. might           B. need             C. should          D. would

5. There was plenty of time; she ______.
  A. mustn’t have hurried               B. needn’t have hurried
  C. may not have hurried               D. wouldn’t have hurried
6. ---Is John coming by air?
  ---He should, but ______ not. He likes taking trains.
  A. must             B. can            C. need              D. may
7. ---______ it be Li Ping who broke the glass?
  ---No. It ______ be Wang Hai who did it.
  A. Could; may       B. Can; can       C. May; must         D. Can; must
8. When the old man was alive, he ______ sit for hours at the door.
  A. would            B. could          C. must              D. might
9. Jack, you ______ play with the knife; you ______ hurt yourself.
  A. won’t; can’t      B. mustn’t; may C. shouldn’t; must           D. can’t; should
10. I’ve decided to take the job and I ______ change my mind.
  A. mustn’t         B. can’t         C. won’t             D. may not
11. She ______ into the thick forest alone on such a dark night
  A. dares not go         B. dares not to go C. dare not to go       D. doesn’t dare to go
12. My parents never remember my telephone number, and they always ______ look it up.
  A. must             B. can            C. should            D. have to
13. ---Where is Jack? I can’t find him anywhere.
   ---He ______ his homework upstairs.
  A. might have done      B. must have done C. might be doing      D. must do
14. He ______ you more help, even though he was very busy.
  A. might have given      B. might give | C. may have given         D. may give
15. ---If he ______, he ______ that food.
   ---Luckily he was sent to the hospital immediately.
  A. was warned; would not take         B. had been warned; would not have taken
  C. would be warned; had not taken