2015情态动词表推测的讲解及练习题.doc

1、 表推测时，英语中只使用 must,may,might,may not 和 cant。这五个表达的语气依次递减：must:一定（语气肯定） 可能性最大may might ； can could 可能 不确定 可能性不大may not：也许不（表否定）cant：一定不；不可能（must 的反义） 可能性为零推测现在的事情用 must,may,might,may not 和 cant+do 或 bee.g.She must be at home now. The boy may play now.推测过去的事情用 must,may,might,may not 和 cant+have donee.g

2、.She might have been ill yesterday. He must have hold the party.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 Ameri

3、can. 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 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 exerc

4、ises 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 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）他准是个工人，是吗？

5、It must have rained last night, didnt 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”。用于肯定句时，表示理论上的，潜在的可能性（有倾向，实际上未必会发生或者不涉及实际是否发生）往往与 sometimes 或者 someone 有关。Accidents

6、 can happen. 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。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

7、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 her homework, has she? 她一定没有完成家庭作业，是不是？could 可用于表示某事有可能发生表示可能性不大的推测。意思相当于 may/might Dont 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

8、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。表示对过去发生的事推测，常常和 have done 连用He was not at home last night . He could/ might have gone to movies. I did

9、nt see her at the meeting yesterday; she couldnt have spoken at the meeting. 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

10、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

11、 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一、单项选择1 John_ come to see us tonight, but he isnt very sure yet. A. may B. need C. cant D. must 2 John isnt in the classroom. He _ play soccer on the playground with Bob.A. can B. must C. should

12、 D. cant3 That _not be her husband . She is still single. A. may B.can C. could D. might 4 You_ go and see a doctor at once because you got a fever.A. can B. must C. dare D. would5 -Can you speak Japanese? -No, I_. A. mustnt B. cant C. neednt D. may not 6 -He_ be in the classroom, I think. -No, he _

13、 be in the classroom. I saw him go home a minute ago. can; may not B. must; may not C. may; cant D. may; mustnt 7 -Is Lena swimming in the pool?-No, she swim. She is terrified of water.A. may not B. must not C. cant D. neednt8 He isnt at school. I think he _ be ill.A. can B. shall C. must D. might9

14、-What do you think “upset” means?- Im not sure. It mean “sad”.may B. must C. can D. should 10 The children_ play football on the road. cant B. can C. mustnt D. must 11.The road is wet . It _last night.A must rain B must have rained C could have rained D can have rained He _you more help , even though he was busy .A might have given B might not give C may not have given D may give 答案 ABBBB CCDAA BA