英语中情态动词的讲解

　　情态动词的用法一直困扰着很多学习英语的童鞋，究竟它的用法是怎样的呢?下面给大家详细的讲解下关于情态动词的用法.
 

　　情态动词讲解如下：

　　1)各个情态动词自身都有一定的词义。

　　2)情态动词不能在句中独立担当谓语。

　　3)情态动词在句中不受任何人称,性,数变化的影响。

　　4) 情态动词后接的不定式(除ought外)都不带to ，即接动词原形。

　　1. 常用情态动词的基本用法

　　can , could 能，会

　　(could可以看作是can的过去式，这两个词除了时态不相同外，在表达意思的许多方面是相同的。当然could也有自己独特的用法。)

　　1)表示脑力或体力上的能力

　　She can sing that song in English.

　　2)表示客观上的可能性

　　Now people can skate on the lake .

　　3)表示主观上的允许

　　Can I ask you some questions about it ?

　　You can not leave here till I come back .直到我回来你才能离开。

　　4)(用于否定句、疑问句或感叹句中)表示猜测、怀疑或惊诧

　　How can / could you be here ? 你怎么会在这儿?

　　She couldn't / can't be so stupid to do that .

　　另外，could还常用于表示较客气委婉的看法、提问及用于虚拟语气的结构中。这时候，could就不可以看作是can的过去式了。而是could自己独特的用法。如：

　　Could you speak a little slowly ?

　　您能稍微说慢一点儿吗?

　　I'm afraid that we couldn't give you any definite answer at this moment .

　　恐怕我们这时候还无法给予您任何确切的答复。

　　I could come earlier if asked .

　　如果要让我早一点来，我可以来早一点。

　　We would appreciate it if you could offer us any help .

　　may , might 或许，可能，可以

　　(might可以看作是may的过去式，这两个词除了时态不相同外，在表达意思的许多方面是相近的。当然may 和might又都有一些各自不同的独特用法。)

　　1)可能性

　　I may be busy from tomorrow on .

　　She thought it might be wise to try her luck here .

　　2)表示允许

　　May I come in ?

　　3) may间或用来表示祝愿，也常用于表示目的或让步的状语从句中:

　　May that day come soon .

　　May you succeed in winning the first prize in the game .

　　must 应该，必须，一定

　　1) 必须　You must hurry up or you'll be late .

　　注意：在这种用法中，回答以must引导的问句时，若是否定答复，不可以用mustn't 而需要用needn't 或是don't have to，因为mustn't意思是"绝不能、一定不要"，而没有"不必"的意思。例如：

　　--Must we hand in our exercises today ? 我们今天必须交作业吗?

　　--Yes , you must .是的，必须交。

　　--No , you needn't (or , you don't have to ).

　　2)表示禁止(用于否定句)

　　You must not speak ill of others .

　　3)表示猜测、推测must常用于肯定句中表示猜测。对现在或未来的事进行猜测时，后接动词原形;对已经发生的事进行猜测时，后接have + 过去分词。例如：

　　You must be tired after working so long .

　　It must have rained last night for it is so wet outside .

　　shall 用于第二人称和第三人称肯定句主要表示下面几层意思：

　　1)许诺

　　I promise that you shall see her again before long .

　　2)命令

　　You shall come to my office immediately .

　　3)决心(表示某事一定会发生)

　　That day shall come .那一天一定会到来。

　　4)规定

　　The renter shall keep the house in a neat and orderly state .

　　情态动词练习题

　　1. Someone is knocking at the door. __it be Venis?

　　---No, it___ be her; she has left for New York this

　　morning. A. might; can’t B. Can; can’t

　　2. --- 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 be B. could it be C. could it have been

　　3. --- I can’t get through to the general manager’s

　　office anyhow.

　　---- The line is busy. Someone __ the telephone.

　　A. must have been using B. must be using

　　4.─　　　　I help you with some shoes, madam?

　　─ Yes, I would like to try on those brown ones. A. Will　　 B. Should　　 C. May　　 D. Must 5.--- This ___ John’s house. It’s number is 101. --I don’t think so. He said his was a large white house but this is a small yellow one. A. can’t be B. must be C. may not be

　　6. I searched for my wallet and it wasn't there. I thought I　　　　 　it at home.

　　A. left　　　B. have left　C. might have left　　 D. could have left

　　7. I 　　asleep because it took me a long time to realize that thetelephone was ringing.

　　A. could have fallen 　 B. should have fallen

　　C. must have fallen 　 D. mustn't have fallen

　　8. ----- You ___ scold such a pupil who always keepsilent so seriously that you ___ hurt him.

　　A.can’t; must B. mustn’t; may C. should; can

　　9. Kunming is called “ Spring City”, but it ___ snow in winter.

　　A. might B. can

　　10. Among the 15-year-old children, some ___ be studying in University while others are still learning to read and write. A. can B. would C. should 11. What we 　　　　　　get seems better than what we have.

　　A. can　　 B. could　　 C. can't　　 D. couldn't 12.─My goodness! I've just missed the train. ─That's too bad. I am sure you 　　　　　　it, if you had hurried. A. could have caught 　 B. had caught　 C. would catch　　 D. could catch 13. Look! What you've done! You 　　　　more careful.

　　A. may be 　 B. had to　C. should have been 　 D. would be 14. 　　　　　　I repeat the question?

　　A. Shall 　 B. Will 　 C. Do you want that 　 D. Do

　　15. Professor Li, many students want to see you. 　　　　　they wait here or outside!

　　A. Do　　 B. Will　　 C. Shall　　 D. Are 16. You 　　　　　read that book if you don't want to.

　　A. haven't　　 B. can't　　 C. mustn't　　 D. needn't

　　17. You ___ get the book on condition that you give itback to me in time. A. should B. must C. shall

　　18. It's nearly seven o'clock. Jack　　　　 be here at any moment.　 　A. must　　 B. need　　 C. can　　 D. should 19. ─ There were already 5 people in the car, but they managed to take me as well. ─ It 　　　　a comfortable journey.

　　A. can't be　　　 B. shouldn't be

　　C. couldn't have been 　 D. mustn't have been 20. Tom ought not to 　　　　　　me your secret, but he meant no harm.

　　A. have told 　　 B. tell

　　C. be telling 　 C. having told