高三一轮复习 专题七 情态动词和虚拟语气讲解与练习

专题七情态动词和虚拟语气
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一、情态动词
1、表能力
can
表示现在有能力做某事
be able to
could
表过去有能力做某事
was/were able to
Eg:I am starving to death. I can eat two bowls of rice.
If you have a good sleep, you will be able to work out this problem.
2、表推测（可能性）
表示具体事情发生的可能性的层次比较
词形肯定式否定式疑问式
must 必定、必然
will 很可能，大概不会，不该会......吗？
would 可能性比will小语气比won’t弱语气比will弱
should 按说应该
ought to 按说应该
can 不可能有可能吗？
could 微弱的可能不可能语气比can弱
may 或许、也许、也说不定可能不
might 比may还弱比may not还弱
注：表可能性时：can/could一般用于否定句和疑问句中，表示疑惑、惊讶或不相信
等，could也可用于肯定句；may/might表可能性不大，不用于疑问句；
Eg:That can’t be Mary, for she is in hospital.（表不相信）
He might be doing his homework now.
They asked if we would do that again.
We should arrive home before dark.
You must be tired after the long journey.
3、表请求、允许
can/could表请求：could不表过去，只表示委婉、客气的语气，但回答时必须用can. may/might表请求：might 不表过去，仅表示语气更加委婉。

will/would表请求：用于第二人称的疑问句。

shall表请求：用于第一、三人称的疑问句。

Eg:Can I use your computer for a while?
---could I use your bicycle? ---Yes, you can. /No, you can’t.
May/might I make a suggestion?
Will you help me with the luggage?
Would you pay me in cash, please?
Shall he come in or wait outside.
4、表必要性
must 表必要性时，意为“必须”
don’t have to/ needn’t do sth,表示“表示不必要做......”
5、“情态动词+have done”用法一览表。

1)must have done 想必/准是/一定做了
否定式：can’t/couldn’t have done
Eg:It must have rained last night for the road is quite muddy.
2)can/could have done 本来能够做某事却没做/过去可能会做
Eg:Can he have gone to his aunt’s?
3)cannot/couldn’t have done 本不能够做某事却做了/过去不可能做某事Eg:He cannot have forgotten it.他不可能忘记那件事。

4)may/might have done 也许/或许已经做......(一般只用于肯定句或否定句) Eg:It’s too late. I think he may have gone to bed.
He may not have finished the work.
5)should/ought to have done 本该做某事但实际上却没做
Eg:You ought to have done this exercise more carefully.
6)should not/ ought not to have done 本不该做某事但却做了
Eg:You shouldn’t have told her the truth.
7)needn’t have done 本不必要做某事却做了
Eg:You needn’t have taken a taxi here, for it was very near to my house.
6、情态动词的其他用法
1）cannot but do sth 表示“不得不，只好做某事”
Eg:I cannot but choose to go. 我只好去。

2）may well/may as well
“may well+动词原形”,意为“完全能，很可能”，相当于to be very likely to Eg:He may well be proud of his son. 他大可为他的儿子感到自豪。

“may as well +动词原形”，意为“最好，满可以，倒不如”
Eg:You may as well do it at once. 你最好现在就做这件事。

二、虚拟语气
1、虚拟语气在非真实条件句的应用
与现在事实相反：条件句：if +主语+动词的过去式（be动词用were）
主句：主语+should/would/could/might+动词原形
Eg:If I were you, I should seize the chance to go abroad.
与过去事实相反：条件句：if+主语+had+过去分词
主句：主语+should/would/could/might+have +过去分词Eg:If you had taken my advice, you would not have failed in the exams.
If+主语+动词的过去式
与将来事实相反：条件句If+主语+were to +动词原形
If+主语+should +动词原形
主句：主语+should/would/could/might
Eg:If he should not come tomorrow, we should put off the meeting till next Monday.
2、使用虚拟条件句时要注意以下4点：
1）错综时间条件句，动词的形式要根据它所表示的时间做出相应的调整。

Eg:If you had followed my advice just now, you would be better now.
If you had studied hard before, you would be a college student now.
2）if 省略句
Eg:If I were at school again (Were I at school again),I would study harder.
If you had come earlier (Had you come earlier), you would catch the bus.
If it should rain tomorrow (Should it rain tomorrow), we would not go climbing. 3）介词短语代替的条件状语从句:with/without/but for
Eg:Without your help, we couldn’t have finished the work ahead of time.
But for your help, ......
4）含蓄条件句
Eg:I was ill that day. Otherwise, I would have taken part in the sports meeting.
I should have given you more help, but I was too busy.
※真题演练
1. I’ve ordered some pizza, so we _______ worry about cooking when we get home tired.
2. It was John who broke the window. Why are you talking to me as if I ______ (do) it.
3. We would rather than our daughter _____ (stay) at home with us, but it is her choice, and she is not a child any longer.
4. My book, the house of hades, is missing. Who _______ have taken it?
5. I still remember my happy childhood when my mother ______ (will) take me to Disneyland at weekends.
6. If Mr Dewey _______ (be) present, he would have offered any possible assistance to the people there
7. No one _____ be more generous; he has a heart of gold.
8. I _______ (not enjoy) myself more---it was a perfect day.
9. If he had spent more time practicing speaking English before, he _____ (be) able to speak it much better now.
10. My mom suggests that we ______ (eat) out for a change this weekend.
11. Harry is feeling uncomfortable. He _______ (drink) too much at the party last night.
12. The door _______ not open, no matter how hard she pushed.
13. ---It rained cats and dogs this morning. I’m glad we took an umbrella.
14. It _______ be the vocabulary that caused you the problem in the exercise because you know a lot of words.
15. He _______ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.
16. Since nobody gave him any help, he _______ have done the research on his own.
17. ---What are you doing this Saturday? ---I’m not sure, but I ______ go to the Rolling Stones concert.
18. The children _____ (get) lost in the wood; otherwise, they would have been at the lakeside camp as a scheduled.
19. I ______ (go) to my cousin’s birthday party last night, but I was not available
20. ---Why are your eyes so red? You ______ have slept well last night. ---Yeah. I stayed up late writing a report.
21. I should not have laughed if I ______ (think) you were serious.
22. ---Do you think George has passed the driving test?
---No,. If so, he _______ (drive) his car to our college yesterday.
※单句填空
1.---Do you like the school?
---Yeah. I only wish the classes ______ (be) a little smaller.
2.According to the factory safety rules, all accidents ______ be reported to the safety officer.
3.One of my rules is that every student _______ come to my class ahead of time.
4.It’s time you _______ (go) home and I’d rather you ______ (come) again tomorrow.
5.If we _______ (interrupt)the day before yesterday, we would have finished the project.
6.It’s true that being constantly exposed to advertisements is annoyed, but it ______ be pleasant sometimes.
7.______ I have a quick word with you? Something important has happened.
8.I’m really thankful to you; without you, I ______ (win) the first prize in the speech contest.
9.Jenny certainly ______ go swimming in the river--- Once bitten, twice shy.
10.The police still haven’t found the lost child, but they’re doing all they ______.
11.If I had known you were coming, I _______ (reserve) a larger table.
12.---I can’t believe that Jeff _____ have quarreled and fought with his boss.
---Well, if one _____ ask for trouble, it just can’t be helped.
13.I ______ have passed my examination easily, but I made too many stupid mistakes.
14.We can hardly believe such a young boy ______ travel around the world all by himself.
15.According to the agreement, no tourist ______ let out how they spent the threes days on the island.
16.Children of divorced parents _______ have difficulty in forming stable relationships themselves.
17.---Is that Nanjing Road over there? ---It ________ be, I’m not sure.
18.There ________ be any difficulty about passing the final test since you have been well prepared.
19.Some aspects of a nurse’s job _______ be boring, and they often _____ work at night.
20.---Where do you think our Chinese translator ______ be?
---She was here only a moment ago.。