情态动词讲义及练习

情态动词can (could), may (might), must, need, ought to, used to，dare (dared), shall (should), will (would),have (to) ,had better.（1）can和could的用法1. 表示能力或客观可能性，还可以表示请求和允许。

注意：①could也可表示请求，语气委婉，主要用于疑问句，不可用于肯定句，答语应用can。

②can表示能力时，还可用be able to代替。

No one can be compared with Yao Ming in playing basketball.2. 表示惊异、怀疑、不相信的态度。

（主要用在否定句、疑问句或惊叹句中）How could you do such a silly thing?3.cannot…too\enough表示“无论怎样……也不过分”，“越……越好”。

You can’t be too careful while driving.I_____ thank you too much for all your help to my son while we were away from home. [2012陕西卷］A. won’tB. can’tC. canD. will（2）may和might的用法1. 表示许可表示请求、允许时，might比may的语气更委婉一些May I take the book out?2. 用于祈使句中表示祝愿。

May you succeed.3.表示推测、可能（只能用于肯定句和否定句，疑问句不能用于此意）。

4.“may as well+动词原形”意为“最好；满可以；倒不如”。

We may as well stay where we are.5. may作“可以”讲时, 其否定式常用“mustn’t”表示“禁止”；must作“必须”讲时, 其否定式是“needn’t”, 表示“不必”。

—May I take this book out of the reading room?—No, you mustn’t. You read it here.I got close enough to hear them speaking Chinese, and I said “Ni Hao” just as I_____ do in China.A. mustB. mightC. canD. should（3）must和have to的用法1. 表示必须、必要。

（must表示主观多一些而have to则表示客观多一些）回答must引出的问句时，如果是否定的回答，不能用mustn’t，而要用needn’t 或don’t have to。

musn’t表示禁止(用于否定句)。

You mu stn’t park here!2. “must be + 表语”的结构表示推测，它的否定或疑问式用can代替must。

3.表示“偏执”；“固执”。

Must you make so much noise?—_____ you interrupt now? Can’t you see I’m on the phone?—Sorry. Sir, but it’s urgent. ［2012重庆卷］A. CanB. ShouldC. MustD. Would（4）shall和should的用法1. 用于第一、第三人称疑问句中, 表示说话人征求对方的意见和向对方请示。

What time shall I pick you up at your house tomorrow, sir？2. 用于第二、第三人称陈述句中, 表示说话人给对方的命令、警告、允诺或威胁。

You shall not get my support if you do such a thing.One of our rules is that every student_____ wear school uniform while at school. ［2012辽宁卷］A. mightB. couldC. shallD. will（5）will和would的用法1. 表示自愿做或主动提出做什么, 如意志、愿望或决心等。

would用于表示过去的情况。

John promised his doctor he would not smoke.I have told him again and again to stop smoking, but he will not listen.2. will可以表示一种习惯性的动作, 有“总是”或“总要”之意。

Every morning he will have a walk along this river.3. would可以表示过去的习惯性动作, 比used to正式, 但没有“现已无此习惯”的含义。

When I was young, I would listen to the radio, waiting for my favorite songs.Days later, my brother called to say he was all right, but _____ say where he was.［2012江苏卷］A. mustn’tB. shouldn’tC. wouldn’tD. mightn’t情态动词表“推测”1. can用于肯定句中可以用来表示推测, 意为“有时会”；用于疑问句中表示推测, 意为“可能”, 有时表示一种惊讶的语气；用于否定句中也可以表示推测, can’t 意为“不可能”, 语气很强烈。

It is usually warm in March, but it can be rather cold sometimes.Mr. Bush is on time for everything. How can it be that he was late for the meeting?2. may用于肯定句中可以用来表示推测, 意为“可能”；用于否定句中也可以表示推测, may not意为“可能不”, 表示一种不太确定的语气。

I might arrive a bit late, so could you save me a place?This may not be done by him.3.must表示推测时只能用于肯定句中, 意为“一定；必定”, 表示十分肯定的语气(在疑问句中或否定句中要用can)。

At this moment, our teacher must be correcting our exam papers.4. should用来表示推测时意为“应该”, 即含有“按道理来说应当如此”的意思。

He should be here on time—he started early enough.It_____ be the postman at the door. It’s only six o’clock.A. mustn’tB. can’tC. won’tD. needn’t“情态动词+have+过去分词”的用法1. can/could have done表示“本来可以做, 而实际上未做”或者“过去可能”, 疑问或否定形式表示对过去发生的行为表示怀疑或不肯定, 其中can’t have done多用于语气强烈的否定, “不可能做过”。

He cannot have forgotten it.I could have worked out the problem, but I didn’t.We_____ the difficulty together, but why didn’t you tell me? ［2012北京卷］A. should faceB. might faceC. could have facedD. must have faced2. may/might have done表示对过去行为的推测, 意为“可能做过”。

might所表示的可能性比较弱, 语气较委婉。

此外might have done可表示“本可能做而实际上未做”。

He might have seen the surprise in my face.3. must have done表示对过去行为的推测, 意为“一定；想必”, 语气十分肯定。

The ground is wet. It must have rained last night.4. should/ought to have done表示过去本来应该做某事而实际上却没有做；shouldn’t/ought not to have done表示过去本来不应该做某事而实际上却做了。

这一用法往往含有责备的意味。

I should have left London before 9, but I didn’t.They_____ have arrived at lunchtime but their flight was delayed. ［2011新课标全国卷］A. willB. canC. mustD. should5. needn’t have done表示本来不必做某事而实际上却做了。

You needn’t have done the washing up.We_____ have bought so much food now t hat Suzie won’t be with us for dinner. ［2012江西卷］A.may notB. needn’tC. can’tD. mustn’t对应训练1. —Shall I inform him of the change of the schedule right now?—I am afraid you_____ , in case he comes late for the meeting.A. willB. mustC. mayD. can2. If you _____ go, at least wait until the storm is over.A. canB. mayC. mustD. will3. Some young people these days just_____ go out of their homes to contact the real world.A. mustn’tB. won’tC. mightn’tD. shouldn’t4. —I don’t like James. Why did you invite him?—Don’t worry. He_____ come. He said he wasn’t certain what his plans were.A. must notB. need notC. would notD. might not5. —How’s your new babysitt er?—We_____ ask for a better one. All our kids love her so much.A. shouldB. mightC. mustn’tD. couldn’t6. Doctors say that exercise is important for health, but it _____ be regular exercise.A. canB. willC. mustD. may7. Some people who don’t like to talk much are not necessarily shy; they _____ just be quiet people.A. mustB. mayC. shouldD. would8. —Sorry, Professor Smith. I didn’t finish the assignment yesterday.—Oh, you_____ have done it as yesterday was the deadline.A. mustB. mustn’tC. shouldD. shouldn’t9. It_____ have been Tom that parked the car here, as he is the only one with a car.A. mayB. canC. mustD. should10. He did not regret saying what he did but felt that he _____ it differently.A. could expressB. would expressC. could have expressedD. must have expressed11. What a pity！Considering his ability and experience, he _____ better.A. need have doneB. must have doneC. can have doneD. might have done（6）dare和need的用法need和dare既可用作情态动词，也可用作实义动词。