情态动词单选题

Unit 2 Modal Verbs 情态动词

◆情态动词的语法特征

1）情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。

2）情态动词除ought 和have 外，后面只能接不带to 的不定式。

3）情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。

4）情态动词没有非谓语形式，即没有不定式，分词等形式。

1.can 表示“能，能力，可能，能够”（用在疑问句或否定句中表示讶异、不相信、推测）

等。注意下面几个结构;:

（1）cannot (help) but do sth.表示“不能不，只能，忍不住，不由得做某事”，eg: When mice are faced with many different foods to choose from, they too cannot help but overeat 当老鼠面对各种食物可以自主选择时，它们也会忍不住吃得过多

I cannot help but tell him the truth.

Cf: can’t help doing sth.

◆注意can和be able to 的区别：

i. can只用于现在式和过去式（could）;be able to可以用于各种时态。例如：

They will be able to tell you the news soon. 他很快就能告诉你消息了。

ii. 后者更强调经过主观努力后的结果，特别是表示成功地做了某事时，用was/were able to，不能用could。例如：

He was able to flee Europe before the war broke out. = He managed to flee Europe before the war broke out.

（2）cannot/can’t…too… “越……越好，怎么也不过分”。注意这个句型的变体cannot…over…，eg:

You cannot be too careful when you drive a car.

The final chapter covers organizational change and development. This subject cannot be overemphasized.

◆注意：could有时不表示时态，如可用来提出委婉的请求，（注意在回答中不可用could）。例如：

--- Could I have the television on? 我能看电视吗？

--- Yes, you can. / No, you can't. 可以/不可以。

2.may (might) 意为“可以（表示允许），可能会、或许会（表示可能性）”，注意以下结

构的用法：

（1）may (might) as well还是…的好，倒不如, eg:

I may as well go to bed. There is nothing on television.

（2）may…but…used to say that although one thing is true, something else which seems very different is also true尽管…但是…，eg:

He may be lazy, but he can work very hard when he feels like it.

（3）may well很可能，极可能, eg:

These are excellent photographs and we may well be able to use them in our magazine.

这是些很不错的照片，我们很有可能把它们用在我们的杂志上。

◆比较may和might

might 表示推测时，不表示时态，只是可能性比may 小。

He might be at home. 他可能在家。

may可以放在句首，表示祝愿。例如：

May God bless you! 愿上帝保佑你！

3.must表示“必须，一定要，得”，通常表示说话人的主观意志，或者要求对方必须做某

事。must 还可以用来表示有把握的推断，意为“一定，准是”.

◆比较have to和must

1）两词都是'必须'的意思，have to 表示客观的需要，must 表示说话人主观上的看法，既主观上的必要。例如：

My brother was very ill, so I had to call the doctor in the middle of the night.

弟弟病得很厉害，我只得半夜里把医生请来。（客观上需要做这件事）

He said that they must work hard. 他说他们必须努力工作。（主观上要做这件事）

2）have to有人称、数、时态的变化，而must只有一种形式。例如：

He had to look after his sister yesterday. 他昨晚只得照顾他姐姐。

3）否定结构中：don't have to表示"不必"，mustn't表示"禁止"。例如：

You don't have to tell him about it.你不一定要把此事告诉他。

You mustn't tell him about it.你不得把这件事告诉他。

◆must表示推测

1）must用在肯定句中表示较有把握的推测，意为"一定"。

2）must表对现在的状态或现在正发生的事情的推测时，must 后面通常接系动词be 的原形或行为动词的进行式。例如：

You have worked hard all day. You must be tired. 你辛苦干一整天，一定累了。（对现在情况的推测判断）

He must be working in his office. 他一定在办公室工作呢。

At this moment, our teacher must be correcting our exam papers. 这时，想必我们老师正在批改试卷。

比较：He must be staying there. 他现在肯定在那里。

He must stay there. 他必须呆在那。

3）must 表示对已发生的事情的推测时，must 要接完成式。例如：

I didn't hear the phone. I must have been asleep.我刚才没有听到电话，我想必是睡着了。The road is wet. It must have rained last night. 地是湿的，昨天晚上一定下雨了。

4）must表示对过去某时正发生的事情的推测，must 后面要接不定式的完成进行式。例如：Your mother must have been looking for you. 你妈妈一定一直在找你。

---Why didn't you answer my phone call? 为何不接我的电话？

---Well, I must have been sleeping, so I didn't hear it.唉，肯定在睡觉，所以没有听见。

5）否定推测用can't。例如：

If Tom didn't leave here until five o'clock, he can't be home yet.如果汤姆五点才离开这儿，他此时一定还未到家。

He can’t be in Shanghai. I’ve just seen him on campus.

Mike can't have found his car, for he came to work by bus this morning.

迈克一定还没有找回他的车，因为早上他是坐公共汽车来上班的。

4.ought to可以表示义务或推测，意为“应该，应当，照说应该”等，其否定形式为oughtn’t

to.

5.should用来表示义务或推测，意为“应当，应该”，与ought to意义接近，但语气稍轻。

should 还有“竟然”的意思，eg:

It’s odd that he should react in this way. 很奇怪，他竟然做出这样的反应。

◆should 和ought to 还可表示"想必一定，按理应该"的意思。例如：

I ought to be able to live on my salary. 靠我的薪水，想必也能维持了。

It ought to be ready now. 想必现在准备好了吧。

They should be there by now, I think. 现在他们该到那儿了。

The poems should be out in a month at most. 诗集估计最多还有一个月就要出版了。

6.need 和dare既可以作情态动词，还可以作实义动词，注意区别。作情态动词时，二者

后面直接接动词原形，否定形式分别为needn’t, dare not; 作实义动词时，二者有人称、数和时态的变化，后面接动词不定式，即need to do sth., dare to do sth., 否定式为doesn’t / don’t / didn’t need to do, doesn’t / don’t / didn’t dare to do.

need doing表示被动意思等于need to be done, eg:

The car needs repairing.

7. will和would

1）would like；would like to do = want to 想要，为固定搭配。例如：

Would you like to go with me? 想和我一块去吗？

2）Will you…?Would you like…? 表示肯定含义的请求劝说时，疑问句中一般用some, 而不是any。例如：

Would you like some cake? 吃点蛋糕吧。

3）否定结构中用will，一般不用would, won't you是一种委婉语气。

Won't you sit down? 你不坐下吗？

8. 情态动词的回答方式

Need you…?－－－Yes, I must. No, I needn't

Must you…?－－－No, I don't have to.

典型例题

1）---Could I borrow your dictionary?

---Yes, of course, you____.

A. might

B. will

C. can

D. should

2）---Shall I tell John about it?

---No, you ___. I've told him already.

A. needn't

B. wouldn't

C. mustn't

D. shouldn't

3）---Don't forget to come to my birthday party tomorrow.

---______.

A. I don't

B.I won't

C. I can't

D. I haven't

8. 注意情态动词完成式的用法有两方面的含义：

(1) 表示已经发生的情况

①must have +过去分词，表示对已发生情况的肯定推测，译为“(昨天)一定……”。如：

My pain must have been apparent the moment I walked into the room, for the first man I met asked sympatheticall y: “Are you feeling all right?”

②can’t/couldn’t have +过去分词，表示对已发生情况的否定推测，译为“(昨天)一定没……”。如：Mary couldn’t have received my letter; otherwise she would have replied before now.

③may/might have +过去分词，表示对已发生的事情做不肯定、可能性很小的推测，或事实上根本没发生，译为“也许……”。如：

Philip may（might）have been hurt seriously in the car accident. 菲力浦可能在车祸中受了重伤。At Florida Power’s Crystal River plant, a potentially serious leakage of radioactive water may have been unknowingly caused by an electrician.

(2) 表示虚拟语气

①needn’t have+过去分词，表示做了不必做的事，译为“其实没必要……”。如：

As it turned out to be a small house party, we needn’t have dressed up so formally.

I dressed very warmly for the trip, but I needn't have done so. The weather was hot.

旅行时，我衣服穿得较多，其实没有必要。那时天很热。

②should /should not have +过去分词，表示应该做某事但实际上未做，或本不应该做但实际上做了, 译为“本(不)应该……”。如：

I regret having left the work unfinished; I should have planned everything ahead carefully.

③ought to have+过去分词，表示动作按理该发生了，但实际上未发生，译为“该……”，与should的完成式含义类似，但ought to 在语气上比should 要强。否定句表示"不该做某事而做了"。例如：

You ought to （should）have been more careful in this experiment. 你当时在做试验时应该更仔细点。

The porter ought to have called the fire-brigade as soon as he saw the fire in the stock, which went up in smoke.

He ought not to have thrown the old clothes away.他不该把旧衣服扔了。（事实上已扔了。）

④could have+过去分词，表示过去本来可以做但却未做，译为“完全可以……”。如：What you said is right, but you could have phrased it more tactfully.

⑤may/might have + 过去分词，表示过去可以做但实际未做，译为“(那样)也许会……”。如：It might have been better to include more punchy statistics and photos of equipment in the introduction to further assist first-time office automation managers.

⑥would like to have done sth表示本打算做某事，但没做。例如：

I would like to have read the article, but I was very busy then. 我想读这篇文章，但太忙了一直没读。

练习：

1.He must have had an accident, or he _____ then.

A. would have been here

B. had to be here

C. should be here

D. would be here

2.The careless man received a ticket for speeding. He ____ have driven so fast.

A. can’t

B. wouldn’t

C. shouldn’t

D. mustn’t

3.As teachers we should concern ourselves with what is said, not what we think _____.

A. ought to be said

B. must say

C. have to be said

D. need to say

4.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

5.At that time we thought the story _____ not be true.

A. could

B. was able to

C. is able

D. must

6.The coffee is very cold. It needs _____.

A. heat

B. to be heating

C. to be heated

D. to be hotted

7.She ____ stay long, because she is afraid he might think her a bore.

A. does not dare

B. dare not to

C. dare

D. dare not

8.You _____ him so closely; you should have kept your distance.

A. shouldn’t follow

B. mustn’t follow

C. couldn’t have been following

D. shouldn’t have been following

9.Some women _____ a good salary in a job instead of staying home, but they decided not to

work for the sake of the family.

A. must make

B. should have made

C. would make

D. could have made

10.You _____ her in her 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. couldn’t have seen

11.Research findings show we spend about two hours dreaming every night, no matter what we

____ during the day.

A. should have done

B. would have done

C. may have done

D. must have done

12.Nina didn’t go to the party last night because she ____ the baby for her brother until 9:00.

A. must have looked after

B. would have to look after

C. had to look after

D. should have looked after

13.“Was she very disappointed at her failure to attend the Graduation Ceremony?”“Yes, she

____ with you.”

A. like to come

B. would like to have come

C. liked to have come

D. would like to come

14.“Must we hand in our reading report by the end of this week?”

“No, you ____.”

A. mustn’t

B. needn’t

C. can’t

D. don’t

15.A lady _____ have too many shoes.

A. may

B. might not

C. should not

D. cannot

Key:

1-5: ACACA

6-10: CDDDD

11-15: CCBBD