情态动词

情态动词的测试要点:
1)情态动词的基本用法: 情态动词的使用主要根据其所表达的含义
2)情态动词 + 动词的完成形式的用法。
3)情态动词的推测性用法。在情态动词的推测性用法中,must, can, may, might, could各用于不同的句型,应注意分辨。对事情的把握由强到弱顺序为must—can—could—may—might 具体使用规律为:
must只用于肯定句中。can/could不能用于肯定句中。may/might不能用于疑问句中。

另外还应注意can't表示"不可能",may not表示"可能不"。考试时,如果有原因说明自己的猜测,一般应该must, can't用而不是may, may not。
如:He can't have stolen the money; he is not such kind of person.
Some pleasant thing must have happened to him. He is so excited.

注意推测性用法中谓语动词发生的时间。
如果推测的为过去的事情,情态动词后则用完成形式。
There must have been no one in, for nobody answered the phone.
如果推测的是正在进行的事情,情态动词后则用动词的进行形式。
They must be talking about something very secret.
如果推测的是现在的状态等,情态动词后则用原形动词
He must be badly ill. He looks so pale.
如果推测的是将来发生的事情,情态动词后同样用原形动词,这时,情态动词只能是may/might。
There may be a terrible storm in the following few days.

4)注意"情态动词+动词的完成形式"所表达的意思与题干意思是否相符。
其它"情态动词+ 动词的完成形式"并不表示推测,而分别表示:
could have done本来能够
He didn't take part in the competition, he _______ though.
A. won B. didn't win C. could win D. could have won

needn't have done 本来没不要
You ________. There was plenty of time.
A. needn't hurry B. can't hurryC. mustn't have hurried D. needn't have hurried

should/ought to have done 本来应该
You _______ me earlier. I could have helped you.
A. should tell me B. should have toldC. need to tell D. needn't have told

shouldn't/oughtn't to have done 本来不应该
You ____ him so closely; you should have kept your distance.
A. shouldn't follow B. mustn't followC. couldn't have been followingD. shouldn't have been following

might have done 本来应该(用来表示一种责备)
You ______ even though you were busy at that time.
A. might help himB. must have helped himC. might have helped him D. should help him

这类题在设计干扰项时,一般都会有情态动词推测性用法的涉及,应注意上下文的逻辑和语意关系。

5)注意常用情态动词的基本句法和表意功能

would的用法:
a) 用于提出提议或邀请
例:Would you like to change a seat? It's warmer here.(您要不要换一下座位?这里暖和些。)
Would you prefer a hardback edition?(您要不要买一本精装本?)

b) 用于提出客气的要求或请求:
例:I would like you to fetch that document for me now.(我想请你现在就帮我把那份文件取来。)
I would like to know more about your plan.(我想更多地了解一下你的计划。)

c) would you mind + doing句型通常用于表示请求对方做一件有一定麻烦的事情,语气一般都非常客气。注意回答时通常是肯定的,以表示愿意做所要求的事情。
例:Would you mind filling in this form?(请您填一下这张表。)
Would you mind repeating what you just said?(请把刚才的话重复一遍好吗?)

d) 用于委婉地表示自己的意见:
例:I would think the journey will take something like two weeks.(依我看,这次旅程大约需要两个星期。)
I would look at the problem a little differently.(我对这个问题的看法略有不同。)

e) 用于表示过去经常性的行为或动作:
例:The retired captain would sit hours on end watching ships sailing past.(退休的船长经常坐在海边观望过往的行船,一坐就是几个小时。)
He would go to bed strictly at 9, and on Sundays would not have lunch anywhere except in that restaurant. (他总是严格地9点上床睡觉。星期日总在那家饭店吃午饭。)

should的用法:
a) 用于表示“应该”或“不应该”的概念。此时常指长辈教导或责备晚辈:
例:You should be here with clean hands.(你应该把手洗干净了再来吃饭。)
例:With all this work on hand, he _______ to the cinema last night.
A) mustn’t B) oughtn’t to go C) wouldn’t go D) shouldn’t have gone
全句的意思是:“他手头又这么多工作,昨夜不该看电影”。本句表达的是昨天已经发生但去不该发生的事情,所以应该用情态动词should的否定式,后接动词的完成式。因而答案是D) shouldn’t have gone。

b) 用于提出意见劝导别人:
例:It would be better if the three of you should work as a team.(最好你们三个人能组成一个小组工作。)
To keep your work, you should prove yourself a resourceful investigator.(你若要保住工作,就该证明自己是个足智多谋的调查员。)

c) 委婉地对别人提出建议或劝告通常用I should / shouldn’t ……if I were you句型:
例:I should hand in a typewritten paper if I were you.(要是我,就交用打字机打出来的论文。)
I shouldn’t worry at all if I were you.(要是我才不着急呢。)

d) 用于表示可能性。should的这一用法是考试中常常出现的考点之一:
例:We should arrive by supper time.(我们在晚饭前就能到了。)
She should be here any moment.(她随时都可能来。)

e) 在以in case或 if引导的从句中,常用should表达一定程度的可能性。
例:I will get some beer ready in case Uncle John should come.(我得准备些啤酒,约翰叔叔可能会来。)
If you should happen to see Mary, give her this package.(如果你碰到玛丽,请把这个包裹交给她。)

f) 用于表示一种惊讶的语气,should的这一用法也是考试中常常出现的考点之一:
例: It is unthinkable that a strong character like Nancy should find a weak-willed man acceptable. (象南希这样很有主见的女子竟然觉得一个意志软弱的男子也可以接受,真让人不可想象。)
I was shocked that she should have said such a thing to you.(她竟然对你说这种话,真让我吃惊。)
其它常用动词的用法,如shall表示"命令"、"威胁"、"许诺"或征求许可,may/might as well等,同学们都应多多注意其用法。

Exercises:

1. Mary's score on the test is the highest in her class; she ____ have studied very hard.
A、may
B、should
C、must
D、ought to
2. You _____ her in here office last Friday; she's been out of town for two weeks.
A、needn't have seen
B、must have seen
C、might have seen
D、can't have seen
3. The room is in terrible mess; it _________ cleaned.
A、can't have been
B、shouldn't have been
C、mustn't have been
D、wouldn't have been
4. She was thankful that she'd had her baby in hospital; otherwise, she thought the baby _____.
A、died
B、had died
C、might have died
D、might die
5. You ______ all those calculations! We have a computer to do that sort of thing.
A、needn't have done
B、shouldn't have done
C、must not have done
D、cannot have done
6. With all this work on hand, he _______ to the cinema last night.
A、mustn't
B、oughtn't to go
C、wouldn't go
D、shouldn't have gone
7. Jenny _______ have kept her word.I wonder why she changed her mind.
A、must
B、should
C、need
D、would
8. —Could I borrow your dictionary﹖ —Yes, of course you _______.
A、might
B、will
C、can
D、should
9. It’s nearly seven o’clock.Jack _______ be here at any moment.
A、must
B、need
C、should
D、can
10. The fire spread through the hotel very quickly but everyone _______ get out.
A、had to
B、would
C、could
D、was able to
11. Mr Brown, many students want to see you, _______ they wait here or outside﹖
A、shall
B、will
C、can
D、would
12. The monitor must be in the reading-room, _______ he﹖
A、mustn’t
B、doesn’t
C、needn’t
D、isn’t
13. Dr Baker must have given a good speech at the conference yesterday, _______he﹖
A、mustn’t
B、didn’t
C、needn’t
D、isn’t
14. —When can I come for the photos﹖ I need them tomorrow afternoon. —They _______ be ready by 12:00.
A、can
B、should
C、might
D、need
15. I told Sally how to get here, but perhaps I _______ for her.
A、had to write it out
B、must have written it out
C、should have written it out
D、ought to write it out
16. He hardly _______ say anything more, since you know all about it.
A、don’t
B、needn’t
C、needs
D、need
17. —Shall I phone Mary? —No,you __________. I've told her.
A、won't
B、needn't
C、shouldn't
D、mustn't
18. —Shall I turn off the TV? —No,you __________
A、won't
B、shouldn't
C、can't
D、couldn't
19. —Shall we go there right now? —No, you __________. It is very dangerous there.
A、won't
B、mustn't
C、needn't
D、couldn't
20. My suggestion is that we __________ have a meeting to discuss it.
A、will
B、can
C、should
D、must