1、1. Look! The light is out in her room. She to bed already.A. must goB. had to goC.must have goneD.has gone2. There were already five people in the car but they managed to take me as well. It_ a comfortable journey.A. cant beB. shouldnt beC. mustnt have beenD. couldnt have been3.My sister met him at
2、the Grand Theatre yesterday afternoon, so he _ your lecture.A. couldnt have attendedB. neednt have attendedC. mustnt have attendedD. shouldnt have attended4.You _ be tired - youve only been working for an hour.A. must notB. won tC. can tD. may not5.- Isn t that Anns husband over there?- No, it _ be
3、him -Im sure he doesnt wear glasses.A. cantB. must notC. wontD. may not6. I was on the highway when this car went past followed by a police car. They_ at lease 150 km an hour.A. should have been doingB. must have been doingC. could have doneD. would have done7. He _ have completed his work; otherwis
4、e, he wouldn t be enjoying himself bythe seaside.A. shouldB. mustC. wouldn t D. can t8. This cake is very sweet. You _ a lot of sugar in it.A should putBcould have putCmight putD must have put9. Tom is never late for work. Why is he absent today? Something _ to him.A must happenBshould have happened
5、Ccould have happenedDmust have happened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。其中性最大， can / could次之， may / might最小。具体用法如下：must 的可能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
6、要表示“一定不、肯定不”的意思时，应用 cant, 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 cant 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
7、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 Its certain / Im 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, isnt he?（现在）他准时个工人，是吗？It must have rained last night, did
8、nt it?（过去）昨晚一定下雨了，是不是？You must have learned English for many years, havent 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。 Cant “一定不”，语气很肯定。 can 在疑问句中意思是“会、可能”。He cant be at home. = It is impossible that he is at home.他一定不在家。（ 2） can /cant 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。
9、They cant be reading in the library.他们一定不在图书馆读书。He cant 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。Its 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cant 时，疑问部分的助动词应与 cant 后面的动词在非推测情况下的用法保持一致.He cant be a teacher, is he?他不是教师，是吗？She cant have finished
10、 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。Dont eat it. It could be poisonous.The plane could be delayed by fog.不要吃它，可能有毒。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） couldnt 表示否定推测，表示某事不可能真实，或由于特定
11、事实或环境某事肯定不会发生。It couldnt 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 couldnt be more wrong.你真是大错特错。I couldnt 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： mig
12、ht 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
