1.用介词或介词短语表示虚拟条件
常用的介词或介词短语主要有without（没有），but for（要不是），in the absence of（如果没有）或were it not for（要是没有），but that（假设……不）等。例如：
Without electricity, there would not be modern industry. 没有电，就没有现代工业。
But for the leadership of the Party, we couldn't live such a happy life.
要不是有党的领导,我们就不会过上如此幸福的生活.
In the absence of gravity, there would be no air around the earth.
如果没有了重力,地球周围就没有了空气.
Were it not for the fact that I saw it with my own eyes, I wouldn't believe it.
若非我那时亲眼看到，我是不会相信的。
Were it not for this misfortune, he might never have been forced into the business of grinding out novels to support his family.
要不是因为这一不幸变故，他可能永远都不会迫于无奈地开始流水线式创作小说养家糊口。
Arrows would continue to fly forward forever in a straight line were it not for gravity, which brings them down to earth.
要不是重力使箭落向地面，它们将永远以直线往前飞行。
Example:
Without gravity, we ______ able to walk.
a. were b. should be c. can be d. should not be
Were it not for the atmosphere, the stars ______ shining at any time in the day.
a. be seen b. can be seen
c. could be seen d. could have been seen
2.用不定式表示虚拟条件
It would be a shame to stop our work half-way. 中途停止工作是很遗憾的。
It would take about 125 million of molecules of water to form a row an inch long.
如果要排成一寸长就需要大约一亿二千五百万个水分子。
Example:
It ______ better to think independently.
a. goes b. looks c. would be d. shall be
3.通过上下文表示虚拟条件
常用的连接词有or, otherwise, but等。例如：
I was very busy yesterday. Otherwise I would have come to see you. 我昨天很忙。否则我会来看你的。
The worn parts have been replaced at the proper time, or a damage might have happened.
磨损的部件及时更换了，否则就会发生破坏。
Example:
He went on foot, but he ______ by bus.
a. might go b. should be gone
c. could have gone d. ought have gone
The traffic was very heavy; otherwise I ______ here 50 minutes sooner.
a. would have been b. would be
c. should be d. had been
4.虚拟语气用在...would(或had)rather（或would just as soon） 从句的句式中，表示与事实相反的愿望。从句谓语动词要用过去式。例如：
I would rather you stayed here. 我宁愿你呆在这里。
I would rather that you didn't do anything. 我宁愿你什么都不做。
I'd just as soon you didn't go there.我宁愿你没有去那儿.
Example:
I'd just as soon ______ those important papers with you.
a. that you won't take b. your not taking
c. please don't you take d. you didn't take
I'd rather you ______ anything about it for the time being.
a. do b. didn't do c. don't d. didn't
5.虚拟语气用在...had hoped that...句型中，表示过去未实现的愿望，意为“原本希望...”，从句谓语用would 原形动词。例如：
I had hoped that she would answer my letter. 我原本希望她能给我回信。
We had hoped that you would change your mind. 我们原本希望你能改变主意。
His father had hoped that he would be a scientist. 他父亲原本希望他成为一名科学家。
Example:
Tom's father had hoped that he ______ into business with him.
a. would go b. would have gone
c. went d. had gone
6.虚拟语气用在had better, had best, had rather, would sooner, would rather, would have句型中，后接原形动词。例如：
You had better close the window. 你最好把窗户关上。
I would rather stay at home. 我宁愿呆在家里。
You had best leave her alone. 你最好别管她。
Would you have me tell her a lie? 你能让我告诉她一个谎言吗？
If you don't mind, I'd rather not see the play. 如果你不介意的话，我宁愿不看这出戏。
I had rather put the books on the desk. 我宁愿把书放在桌子上。
Liu Hu Lan would sooner die than surrender. 刘胡兰宁死不屈。
Example:
I ______ do that if I were given the choice.
a. would rather not b. rather not
c. do not rather d. would not rather
“I haven't felt well for a week.” “You ______ see a doctor.”
a. had ought to b. had better
c. should have to d. had rather
______ do it myself than try to persuade a stubborn fellow like you.
a. I'd rather b. I'd better
c. I rather d. I'd like
练习：
1.I would rather ______ a book than watch TV.
a. read b. reading c. to read d. have read
2.You were late again this morning. I think you had better ______ on time.
a. to start to be b. start being
c. started being d. to be
3.She ______ into the water but that I caught her.
a. would fall b. would have fallen
c. has fallen d. wouldn't fall
4.He had hopped that his son _____ an engineer.
a. will be b. be c. is d. would be
5. I would just as soon ______ those heavy boxes with you.
a. that you won't take b. your not taking
c. please don't you take d. you didn't take
6.I did not call to make my airline reservation, but I _____.
a. must have b. may have c. should have d. shall have
7. ______ your advice, I would never have got the job.
a. But for b. As for c. Apart from d. Except for
8. With all this work on hand, he ______ TV last night.
a. mustn't watch
b. shouldn't have watched
c. wouldn't watch
d. ought not to watch
9.He must have missed the train, or he ______ here then.
a. should be b. would be
c. would have been d. had to be
10.Without electronic computers, much of today's advanced technology ______ achieved.
a. must have been b. could have been
c. should have d. would not have been
11. I was in a hurry that day. Otherwise I ______ to talk to you.
a.had stopped b. would have stopped
c. stopped d. had to stop
12. “I'm surprised to learn that you're going back to Chicago.”
“Yes. I'd hoped that I ______ have to go back again, but I do.”
a. don't b. won't c. hadn't d. wouldn't
13. Better ______ the butcher than the doctor.
a. to pay b. pay c. paying d. paid
14. I would have come sooner but I ______ that you were waiting.
a. didn't know b. hadn't known
c. haven't known d. couldn't have known
15. You had better ______ so many questions.
a. not to ask b. ask not c. not ask d. not asking
16. “John wants to see you today.” “I would rather he ______ tomorrow than today.”
a. comes b. came c. has come d. should come
17. Life today ______ very different without iron and steel.
a. would be b. is not c. will be d. has been
18. It ______ wrong not to take this into consideration.
a. is said b. will be c. would be d. can be
19. I would sooner not _____ here.
a. have waited b. waiting c. waited d. wait
20. Time is running out. Hadn't we better______?
a. got started b. got start
c. get started d. to get starting
参考答案:abadd cabcd bdbac bacdc
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