英語語法網
英語語法學習中，對於虛擬語氣的應用也是比較常見的。下面是本站小編給大家整理的英語語法網的相關知識，供大家參閱!
1.虛擬語氣用在 suggest, demand, insist, ask, move, advise. desire, order, propose, require, recommend, request, maintain, vote 等表示建議，命令，請求的動詞後的賓語從句中，從句的謂語用 should + 原形動詞，但美國英語中常要省去 should 。例如：
I suggest we start at once.
They propose that you (should) read the rules carefully.
The commander ordered that the soldier fire at the enemy.
He insisted that he go there on foot.
I move that the meeting be adjourned. 我提議休會. move:(在會議上)提議，動議
Example:
He insisted that we all ______ in his office at one o'clock.
a. be b. to be c. would be d. shall be
He asked that it ______ done right away.
a. is b. be c. shall be d. must be
He recommended that John ______ with him.
a. must go b. went c. will go d. go
2.虛擬語氣用在 It is + 形容詞(或過去分詞)+ that... .的主語從句中，表示要求，建議，提議，命令，請求等，英國英語中從句的謂語用“should +原形動詞(或完成式)構成”，而美國英語中則要求用原形動詞。該句型中常用的形容詞或過去分詞有：advisable, desirable, essential, important, better, keen, natural, necessary, probable, possible, strange, vital, desired, demanded, requested, suggested, recommended, required 等。例如：
It is necessary that the machine (should) be oiled once a week.
It is important that everyone (should) obey the law.
It is suggested that you take a walk after supper.
Example:
It is necessary that he ______ in time to attend the meeting.
a. come b. came c. would come d. need come
It was proposed that the matter ______ discussed at the next meeting.
a. would be c. will be c. was d. be
It is strange that she ______ in the last examination.
a. should have failed b. have failed c. would fail d. failed
3.虛擬語氣用在與表示建議，要求，提議，命令，請求等意思有關的同位語從句和表語從句中，英國英語中要求從句謂語用“ should + 原形動詞”，而美國英語中則要求用原形動詞， 但在 as if, as though引導的表語從句中，從句中謂語用動詞過去式或過去完成式，表示對現在或過去的虛擬。例如：
He complied with the requirement that the experiment (should) be done tomorrow.
他同意明天再做實驗的要求。虛擬語氣用在其它名詞性從句中
He looks as if he were tired.他面帶倦容。
We agree to the suggestion that they (should) work on night shifts in turn.
我們同意輪流值夜班的建議。
His order is that you (should) send the materials to the work site at once.
他的命令是你們要把材料立即送到工地。
Example:
Your advice that she ______ till next week is reasonable.
a. will wait b. is going to wait c. waits d. wait
Jane appears as though she ______ the secret.
a. knows b. has known c. had known d. knew
He looked as if he______ ill for a long time.
a. was b. were c. has been d. had been
4.虛擬語氣用在 It is (high, about) time (that) 句型中，定語從句中謂語用動詞過去式，意指將來。例如：
It is time (that) we went home.
It is high time we had the meeting.
It is time you left.
It is time that I was off.
注：如果主語是單數第一，三人稱，動詞 be常用 was 。
Example:
We've been sitting here doing nothing about it for days. It's time we ______ the problem.
a. shook hands with b. got to brass tacks with
c. got to grips with d. reached the bottom of
詞組 get (or come) to grips with 爲“開始努力對付”。
It is high time we _______ off.
a. are b. were c. be d. will be
It is ______ we did something about redecorating the sitting room.
a. high time b. long time
c. good time d. full-time
練習題：
1. The doctor suggested that he ______ a short leave of absence.
a. will take b. would take c. take d. took
2. We demand that atomic weapons ____ .
a. be prohibited b. will be prohibited
c. are prohibited d. ought to be prohibited
3. It was suggested that transistors _____ in such devices.
a. should be used b. should use
c. can be used d. were using
4. The tutor recommended that she _______ this book.
a. must buy b. buy
c. should have bought d. buys
5. The housemaster was strict. He requested that we ______ television on week nights.
a. not watch b. must not to watch
c. not be watching d. have not watched
6. My father did not go to New York, the doctor suggested that he ______ there.
a. not to go b. won't be
c. not go d. not go to
7.I demanded that the students each ______ a plan for the summer vacation.
a. would make b. will make c. make d. made
8. It is surprising enough that such a horrible thing ____ there.
a. happened b. will happen
c. should happen d. has happened
9. It was urgent that she ______ the master immediately.
a. call b. calls c. called d. would call
10. He looks as if he _____ nothing about it before.
a. knows b. had known
c. has known d. wouldn't know
idea is that we ______ the challenge.
a. ought accept b. will accept
c. accept d. are accepted
12. The sun rises in the east and sets in the west, so it seems as if the sun ______ round the earth.
a. is circling b. has circled
c. should circle d. were circling
13. It was suggested at the meeting that effective measures _______ to solve the problem.
a. be taken b. must be taken
c. were taken d. take
14. It's advisable that he ______ with a clearly defined goal in mind.
a. must go b. go c. will go d. goes
seemed as if all of sudden the animal _____ danger in the air.
a. has smelt b. had smelt
c. smelt d. would smell
is better that the book ______ on the low stool.
a. put b. puts
c. should be put d. be put
moved that the report ______.
a. should accept b. should be accepted
c. be accept d. would be accepted
professor gave orders that the test ______ before 5:30.
a. be finished b. will be finished
c. will finish d. shall finish
's time he ______ something for his coming examination.
a. do b. does c. will do d. did
was essential that all the necessary documents ______ to the dean's office before Friday.
a. be handed in b. must be handed in
c. had been handed in d. should hand in
is highly desirable that a new president _____ for our institute.
a. appointed b. be appointed
c. has been appointed d. is appointed
22. The government ordered that the pollution problem of this city ______ within six months.
a. would solve b. would be solved
c. should be solved d. must solve
23. It is natural that much research ______ to overcome corrosion.
a. should make b. will make
c. is made d. should have been made
24. It is important that a consultant engineer ______ familiar with modern developments.
a. is b. being c. be d. has been
25. Since her blood pressure is much higher than it should be, her doctor insists that she _____.
a. will not smoke b. is not smoking
c. didn't smoke d. not smoke
英語語法網：虛擬語氣用在條件狀語從句中虛擬語氣是一種特殊的動詞形式，表示所說的話不是一個事實，而只是一種假設，願望，建議，懷疑，猜測或不大可能實現的空想。
I.虛擬語氣用在條件狀語從句中
虛擬語氣用在條件狀語從句中，通常從句由連詞if 引導。
1.與現在事實相反的虛擬條件句
條件狀語從句主句
If +主語 +動詞過去式主語+ would, should, could, might+原形動詞
(be的過去式用were)
例如：
If I feared death, I wouldn't be a communist.
(劉胡蘭)怕死就不做共產黨員。
If there were no air, we couldn't live.
如果沒有空氣，我們就不能生活。
Example:
I would ask George to lend us the money if I ______ him.
A. had known B. knew C. have known D. know
I _____ it to him if I thought he would understand.
A. shall explain B. will explain C. would explain D. explain
2.與過去事實相反的虛擬條件句
構成
條件狀語從句主句
If + 主語 + 動詞過去完成式主語 + would, should, could, might+have + 過去分詞
例如：
If you had come a few minutes earlier, you would have met him.
如果你早來幾分鐘，你就會碰上他。
If there had been no air in the tube, the result of the experiment would have been more accurate.
如果試管中沒有空氣，實驗結果就會更精確。
Example:
If you hadn't gone with Tom to the party last night, _______.
A. you would meet John already
B. you won't have missed John
C. you will have met John
D. you would have met John
3.與將來事實相反的虛擬條件句
構成
條件狀語從句主句
If + 主語+ should +原形動詞主語+would,should,could,might或were+不定式+原形動詞
例如：
If he were to come tomorrow, things would be easier.
假如他明天會來，事情就容易辦了。
If the sand should be broken up, it would give out much energy.
如果沙子能被分解，它會釋放出大量的能量。
注：在表示與將來事實相反的虛擬條件句中，從句中的should有時可以省略。如：
If he make the design, he might do it in some other way.
要是他來搞這個設計，他可能用另外的方法設計。
Example:
If the sea ____ to rise 50 feet, India would become an island.
A. will B. is C. was D. were
If you ____ to see Mary, what would you tell her?
A. are B. will be going C. must D. were
We might still catch the train if we ___.
A. make hurry B. haste
C. make haste D. hastily
4.錯綜時間的虛擬語氣
在一些含有虛擬語氣的句子中，如果主句與從句的謂語表示不同的時間，虛擬語氣可有不同形式，即主句與從句各自按自己的時間構成虛擬形式。例如：
If I had met him before, I could recognize him.要是我以前遇見過他，我就能認出他了。
(從句表示與過去事實相反，主句表示與現在或將來事實相反)
If we were driving at a speed of 100 Li an hour, we would have arrived there 2 hours ago. 如果我們的行車速度每小時100裏，兩小時以前我們就會到達那裏了。
(從句與現在事實相反，主句與過去事實相反)
Example:
If you _____ that late movie last night, you wouldn't be sleepy.
A. haven't watched
B. didn't watch
C. hadn't watched
D. wouldn't have watched
5.省略連詞if
在條件狀語從句中，如果有were, should, had，可以把連詞if 省去，把 were, should, had 放在句首，構成條件意義。例如：
Should it rain tomorrow, what would you do? 萬一明天下雨，你怎麼辦?
Were there no friction, we could not walk. 要是沒有摩擦力，我們就不能行走。
Had we known about the new method, we should have applied it earlier.
如果我們過去知道這種新方法，我們早就應用了。
Example:
Had Alice been more hardworking, she _______.
A. had not failed B. would not fail
C. could not be failed D. would not have failed
_______ today, he would get there by Friday.
A. Would he leave B. Was he leaving
C. Were he to leave D. If he leaves
______ difficulties, we would be successful.
A. Should we overcome B. Would we overcome
C. Might we overcome D. Could we overcome
6.虛擬結構中省略主句或從句
虛擬結構中有時可省去主句或從句，並不影響意義的完整。
(1)省去條件從句
That would be fine. 那太好了。(省去了if you would come 或類似條件)
I wouldn't pass up the chance to visit China. 我不會放棄訪問中國的機會。
We might have produced more coal. 我們可能生產出更多煤炭。
注：省略條件句，在試題中很少見到。
(2)省去主句，常用以表示願望。從句謂語多用過去時或過去完成時。
If only she were here. 假如她在這兒該多好啊!
If only he lived! 假如他活着該多好啊!
If only I had known it before. 如果我早先知道這件事，那就好了。
Example:
If only it _____! but it is too late.
A. is avoided B. has avoided
C. could be avoided D. can be avoided
If only everything _____ out as we wanted it to in life!
A. is working B. worked
C. works D. has worked
英語語法網：虛擬語氣用在其它狀語從句中1.虛擬語氣用在由as if, as though 引導的方式或讓步狀語從句中，一般情況下，如果主謂語動詞爲現在時，從句謂語多用過去時;如果主句謂語爲過去時，從句謂語多用過去完成時。虛擬語氣用在 even if, even though, whatever引導的狀語從句中，從句謂語可參照由if引導的虛擬條件從句的謂語，一般用過去時或過去完成時。例如：
This old machine runs as if it were a new one.
The old worker works as though he were a young man.
Even though she had been here very soon, she would not catch the train.
Example:
He has just arrived, but he talks as if he ______ all about that.
a. know b. knows c. known d. knew
I can't stand him. He always talks as though he _____ everything.
a. knew b. knows c. has known d. had known
______ I used a lot of examples I still could not get my idea across.
a. Since b. But that c. Now that d. Even though
2.虛擬語氣用在so that, lest (唯恐), in case (萬一), unless, in order that(爲了，以便), that(爲了，以至於), for fear that (生怕，以免), on condition that (如果)等引導的目的，條件狀語從句中，從句謂語 may 或 might+原形動詞，也有用 should, can, could+原形動詞構成的。例如：
The teacher explained the law once more in order that we might understand it better.
Some people eat so that they may live. Others seem to live in order that they may eat.
一些人吃是爲了生存，而另一些人似乎是活着就是爲了吃。虛擬語氣用在其它狀語從句中
I left him a note with my address on for fear that he should not know where to see me.
The heroes gave their lives that we might live a happy life.
爲了我們過上幸福生活，英雄們獻出了自己的生命。
Example:
In case I ______, I would try again.
a. will fail b. would miss c. should fail d. shall miss
You should exercise vigilance _____ you should be killed.
a. so that b. lest c. therefore d. that
3.虛擬語氣用在由 “whether” 引導的讓步狀語從句中，從句謂語用原形動詞。例如：
All engines work on this principle, whether they be large or small.
所有發動機都按這一原理工作，無論它們是大還是小。
We must finish the work before we go home, whether it be early or late.
無論時間早晚，我們必須在回家前幹完工作。
All matter, whether it be gas, liquid or solid, is made up of atoms.
所有物質，不論是氣體，液體，或固體，都是由原子構成。
在此句型中，可省去 whether ，而將be放在主語前。例如：
Be it so, we must continue to do the test.
We must do our best to fulfil the task, be it ever so hard.
Example:
______ I'll marry him all the same.
a. Were he rich or poor b. Be he rich or poor
c. Whether rich or poor d. Being rich or poor
練習題：
1.______, I must do another experiment.
a. It is ever so late
b. Ever so late it
c. Be it ever so late
d. Whether be it ever so late
young driver looked over the engine carefully lest it ______ on the way.
a. goes wrong b. would go wrong
c. went wrong d. should go wrong
ines are often oiled so that they ______ well.
a. ran b. runs c. should run d. running
if he ______ very busy, he would have kept on learning English.
a. had been b. was c. were d. had being
osing the weather ______ bad, where would you go?
a. is b. will be c. was d. were
6. ______, he could not succeed.
a. However, he tried that
b. He tried however hard
c. However he could try
d. However hard he tried
7. Even though the enemy ______ wings, they couldn't escape from our encirclement.
a. had b. had had c. have d. has
described the accident as if she ______ it herself.
a. saw b. has seen c. had seen d. sees
came to meet us at the station for fear that we ______ the wrong way.
a. take b. should take c. took d. had taken
car looked very dirty, as though it ______ hundreds of miles.
a. run b. runs c. has run d. had run
teacher spoke slowly in order that we ______ no difficulty in following him.
a. should have b. had
c. will have d. didn't have
magnets behave the same, ______ they large or small.
a. how b. are c. be d. were
the beginning he didn't want to speak English lest he _____ mistakes.
a. will make b. should make
c. would make d. can
14. I remember the whole thing as if it ______ yesterday.
a. happen b. happens c. happened d. happening
stayed at home for a few days so that she _____ her mother.
a. takes care of b. took care of
c. might took care of d. might take care of
took up the meter with care for fear that it _____ .
a. is damaged b. to be damaged
c. should be damaged d. was damaged
17. In many cases the heating effect is neglected as if there ______ no flow of current along the wire.
a. are b. were c. is d. being
18.I'll put the money on the table just in case you ______ it.
a. might need b. would need
c. needed d. may have needed
iding you ______ the opportunity to go abroad, which country would you want to visit first?
a. have b. will have c. had d. have had
business of each day, ______ selling goods or shipping them, went quite smoothly.
a. it being b. was it c. it was d. be it
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