情态动词mustcancouldmaymight表推测用法

情态动词must, can, could, may,might表推测的用法：情态动词中的must, can, could, may, might都表推测。

其中must的可能性最大，can / could次之，may / might最小。

具体用法如下：1. must的用法（1）表示推测“可能性”时，意思是“一定、准是”，语气较肯定，较有把握。

He must be American. = It is certain that he is American. 他准是个美国人。

（2）must表推测只能用于肯定句。

如果要表示“一定不、肯定不”的意思时，应用can`t,如询问某种可能时，应用can。

He must know my address. 他肯定知道我的地址。

（一定）He can`t know my address. 他肯定不知道我的地址。

（一定不）Can he know my address? 他知道我的地址吗？（询问可能性）（3）must表示推测时，可以推测现在/正在发生的动作/过去发生的动作。

He must have a car now. （现在）他一定有辆小汽车。

He must be doing his exercises in the classroom.（正在进行）他一定在教室里做练习。

He must have finished the work.（过去发生）他一定已完成了工作。

注：must表示推测时很少用于将来的情况。

一般不用He must come tomorrow.可用It`s certain / I`m sure that he will come tomorrow.（4）在反意疑问句中，当附属部分含有表示推测意义的must时，疑问部分的助动词应与must后面的动词在非推测情况下的用法保持一致。

He must be a worker, isn`t he? （现在）他准时个工人，是吗？It must have rained last night, didn`t it? （过去）昨晚一定下雨了，是不是？You must have learned English for many years, haven`t you? （完成时）你一定学了好多年英语，是吗？2. can / could的用法（1）can表示推测“可能性”时，往往用于否定句或疑问句。

Can`t“一定不”，语气很肯定。

can在疑问句中意思是“会、可能”。

He can`t be at home. = It is impossible that he is at home. 他一定不在家。

（2）can /can`t后可接进行时/完成时，表示对现在发生的动作或过去发生的动作进行推测。

They can`t be reading in the library. 他们一定不在图书馆读书。

He can`t have gone to Shanghai for I saw him a minute ago.他不可能去了上海，我刚才还看见他。

It`s so late. Where can she have gone? 天晚了，她可能去哪儿了呢？（3）在反意疑问句中，当陈述部分含有表示推测意义的can`t时，疑问部分的助动词应与can`t后面的动词在非推测情况下的用法保持一致.He can`t be a teacher, is he? 他不是教师，是吗？She can`t have finished her homework, has she?她一定没有完成家庭作业，是不是？（4）could可用于表示某事有可能发生或可能是事实。

Don`t eat it. It could be poisonous. 不要吃它，可能有毒。

The plane could be delayed by fog. 飞机可能会因为雾晚点。

（5）could还可以用于表示客气、委婉、礼貌的请求语气。

Excuse me, could you tell me the way to the bus station?Could you help me?（6）couldn`t表示否定推测，表示某事不可能真实，或由于特定事实或环境某事肯定不会发生。

It couldn`t possibly be poison. 这不可能是毒药。

注：有时与形容词的比较级连用强调某人或某物不可能再更多地具有某种属性。

You couldn`t be more wrong. 你真是大错特错。

I couldn`t be happier. 我简直是幸福极了。

3. may和might的用法（1） may, might表示推测“可能性”时，意思是“可能”、“也许”，语气没有must肯定。

He may / might be American. = It is possible that he is American.他可能是个美国人。

注：might不表示过去时态，只是语气上比may更委婉，表示的可能性更小。

（2）may, might表推测时，可以用于否定句，意思是“可能不、也许不”，但不用于疑问句。

He may / might not be at home. 他也许不在家。

（3）may, might可以推测现在正在发生的动作或过去发生的动作。

He may / might be sleeping now. （现在）他可能正在睡觉。

The boy may / might not be watching TV at home. （现在）这个男孩可能没在家看电视These students may / might have seen the film before.（过去）这些学生以前可能看过这部电影。

（4）may, might还可以推测将来的情况。

I think we should take raincoat with us, it may rain.我想我们应该带上雨衣，可能要下雨了。

She might not come this afternoon. 她今天下午可能不来了。

情态动词和虚拟语气练习40题从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。

1.—Are you in a hurry？—No，in fact I’ve got plenty of time. I ___wait.A.mustB.needC.mayD.should2.—Someone is knocking at the door. ___ it be Venis？—No，it ___ be her；she left for New York this morning.A.Can；mustn’tB.Might；can’tC.May；doesn’tD.Can；can’t3.He didn’t agree with me at first，but I ____ persuade him to sign the agreement later.A.couldB.mightC.shouldD.was able to4.—Is there a movie on in the cinema tonight？—There___ be. I will phone the cinema and find it out.A.mightB.shouldC.canD.could5.You ___ be careful when you cross here —the traffic lights aren’t working.A.canB.ought toC.mightD.may6.You ___ out last night. I called you several times，but nobody answered.A.must have beenB.must beC.might have beenD.could be7.You ___ fail to pass the entrance examination if you don’t study harder.A.shallB.couldC.mustD.should8.When I was studying at Beijing University，I ___ take a walk along the lake every evening.A.willB.wouldC.couldD.shall9.The party turned out to be a failure. I would rather ___ it.A.not have attendedB.not attendC.not to attendD.not to have attended10.Sir，you ___ be sitting in this seat. It is for women or children only.A.can’tB.oughtn’t toC.won’tD.needn’t11.—Shall I tell Li Ming about the matter？—No，you ___ . He has known about it already.A.oughtn’t toB.needn’tC.shouldn’tD.mustn’t12.—Must I take a bus？—No，you ___ . You can walk there.A.must notB.don’tC.don’t have toD.had better not to13.—Why do you make me do so？—I am sorry that you ___ do such a thing.A.wouldB.canC.shouldD.may14.—Will you stay for lunch？—Sorry，I ___ . My brother is coming to see me.A.mustn’tB.can’tC.needn’tD.won’t15.What would have happened ___ ，as far as the riverbank？A.if Bob has walked fartherB.if Bob should walk fartherC.had Bob walked fartherD.should Bob walk farther16.Oh，Jane，you’v e broken another glass. You ought ___ when you washed it.A.be carefulB.to careC.have caredD.to have been careful17.It’s high time we ___ to th e theater.A.will goB.shall goC.are going toD.went18.—Could I use your telephone？—Yes，of course you ___ .A.couldB.willC.canD.might19.It’s strange that they ___ nothing about this matte r.A.should knowB.would knowC.had knownD.knew20.—Do you still remember the day when we went to the Great Wall？—I can’t remember it well，but ___ sometime last autumn？A.might it beB.could it have beenC.could it beD.must it have been21.—I can’t get through to the general manager’s office anyhow.—The line is busy. Someone ___ the telephone.A.must useesC.must have been usingD.must be using22.He suggests we ___ to the cinema at once，otherwise we will be late.A.must goB.goC.will goD.would go23.If only he ___ me yesterday!A.had seenB.would seeC.should seeD.saw24.If you ___ wait a moment，I’ll go and find our manager.A.canB.shouldC.willD.must25.—It is rather cold here. Shall we light a fire？—No，we ___ because things are easy to catch fire.A.won’tB.can’tC.mustn’tD.needn’t26.If I ___ you，I ___ more attention to English idioms and phrases.A.was；shall payB.am；will payC.would be；would payD.were；would pay27.—Would you have told him the answer had it been possible？—I would have，but I ___ so busy then.A.had beenB.wereC.wasD.would be28.—Can children swim in this pool？—Yes. However，at no time ___ they do so by themselves.A.dareB.shouldC.needD.could29.Kunming is called“Spring City”，but it ___ snow in winter.A.shallB.canC.mustD.might30.—What’s the matter with you？—Oh，I’m not feeling well in the stomach. I ___ so much fried fish just now.A.shouldn’t eatB.mustn’t have eatenC.shou ldn’t have eatenD.mustn’t eat31.—You look so upset. What’s wrong with you？—The door ___ . Can you help me？A.won’t openB.won’t be openedC.can’t openD.can’t be opened32.—Mum，I climbed to get the Teddy Bear from the top of the shelf.—My goodness！You ___ yourself. You mustn’t do that next time.A.must have hurtB.should have hurtC.may have hurtD.can have hurt33.Children under 12 years of age in that country ___ be under adult supervision when he is in a public library.A.mustB.mayC.canD.need34.“The interest ___ be divided into five parts，according to the agreement made by both sides，” declared the judge.A.mayB.shouldC.mustD.shall35.—I don’t mind telling you what I know.—You ___ . I’m not asking you for it.A.mustn’tB.may notC.can’tD.needn’t36.—Mum，I’ve been studying English since 8 o’clock. ___ I go out and play with Tom for a while？—No，I’m afraid not. Besides，it’s raining outside now.A.Can’tB.Wouldn’tC.Dare notD.Won’t37.—Who is the girl standing over there？—Well，if you ___ know，her name is Mabel.A.mayB.canC.must D shall38.The driver has drunk too much wine and dangerous things ___ happen at any time.A.shouldB.canC.mustD.need39.We ___ booked. Look，this restaurant is almost empty.A.must haveB.can’t haveC.should haveD.needn’t have40.Listen! The fire engine is roaring. There ___ be a fire somewhere.A.shouldB.mustC.willD.ought to【答案及部分解析】1～5 CDDAB 6～10 AABAB 11～15BCCBC 16～20 DDCAB 21～25 DBACC 26～30 DCBBC 31～35 ACADD 36～40 ACADB1. may表示“可以”。