(完整版)高中英语虚拟语气练习题(附答案)

高中英语虚拟语气单选题50题(含答案)1.If I were you, I ______ study harder.A.willB.wouldC.shallD.should答案：B。

解析：本题考查对现在情况的虚拟语气。

if 引导的虚拟条件句，对现在情况虚拟时，从句用一般过去时，be 动词一律用were；主句用“would/should/could/might + 动词原形”。

选项A 是将来时；选项C 通常用于第一人称；选项D should 表示“应该”，在这里不如would 更符合虚拟语气的用法。

2.If he had time, he ______ go to the park.A.willB.wouldC.shallD.should答案：B。

解析：与上一题类似，对现在情况虚拟。

从句是if he had time，主句用would + 动词原形。

选项A 是将来时；选项C 一般不用于这种情况；选项D should 在此处不合适。

3.If I had a car, I ______ drive to school.A.willB.wouldD.should答案：B。

解析：对现在情况虚拟，从句用一般过去时，主句用would + 动词原形。

选项A 是将来时；选项C 不用于此处；选项D should 意思不对。

4.If she were rich, she ______ buy a big house.A.willB.wouldC.shallD.should答案：B。

解析：同样是对现在情况虚拟，主句用would + 动词原形。

选项A 是将来时；选项C 一般不这样用；选项D should 不符合。

5.If we had more time, we ______ finish this project.A.willB.wouldC.shallD.should答案：B。

解析：对现在情况虚拟，主句用would + 动词原形。

高一英语虚拟语气运用练习题40题含答案解析1.If I were you, I ______ study harder.A.willB.wouldC.shallD.should答案解析：B。

if 引导的虚拟语气中，表示与现在事实相反，从句用一般过去时，主句用“would/could/should/might+动词原形”。

A 选项will 一般用于一般将来时，不符合虚拟语气的用法；C 选项shall 一般用于第一人称的将来时，也不符合；D 选项should 意思不对。

2.I wish I ______ a bird and could fly freely.A.amB.wereC.wasD.be答案解析：B。

在wish 后的宾语从句中，表示与现在事实相反，要用虚拟语气，be 动词用were。

A 选项am 是一般现在时的用法；C 选项was 一般用于比较正式的场合，但在虚拟语气中不用；D 选项be 一般在不定式等情况下使用。

3.If he had time now, he ______ with us.A.will playB.would playC.shall playD.should play答案解析：B。

if 引导的虚拟语气中，表示与现在事实相反，从句用一般过去时，主句用“would/could/should/might+动词原形”。

A 选项will play 一般用于一般将来时，不符合虚拟语气的用法；C 选项shall play 一般用于第一人称的将来时，也不符合；D 选项should play 意思不对。

4.She would be happy if she ______ more friends.A.hasB.hadC.haveD.having答案解析：B。

if 引导的虚拟语气中，表示与现在事实相反，从句用一般过去时，主句用“would/could/should/might+动词原形”。

高中英语─虚拟语气专项练习（附答案）1.If my brother _____ here last Sunday, he _____ me from going.A.had been; would have preventedB.had been; would preventC.were; would preventD.were; would have prevented2.The judge ordered that the thief _____ punished.A.would beB.should beC.were to beD.must be3.He talked as if _____ for many years.A.is living thereB.was living thereC.has lived thereD.had lived there4.I wish I _____ you yesterday.A.sawB.did seeC.had seenD.were to see5.The rice _____ if you had been more careful.A.wouldn't be burningB.would not burnC.would not have been burnedD.wouldn't be burnt6.Without electricity,human life _____ quite different today.A.wouldB.will beC.would have beenD.would be7.I'd rather you _____ anything about it for the time being.A.don't doB.didn't doC.hadn't doneD.won't do8.If he _____ in a day or two,I would wait for him.A.returnsB.should have returnedC.were to returnD.have returned9.I would go to the concert but I _____ no time.A.hadB.had hadC.haveD.have had10.How nice it _____ if I _____ a sister like you!A.should be; had beenB.would be; had beenC.would be; hadD.were; had11. _____ in your position, I would go.A.If IB.Were IC.If was ID.If I am12. _____ five minute earlier, you could have seen them off.A.If you should arriveB.If you arrivedC.Had you arrivedD.Should you arrive13.I am glad we had a map. I am sure we _____ if we _____ one.A.would have got lost; hadn't hadB.would get lost; hadn'tC.couldn't have get lost; had hadD.may get lost; don't have14.The doctor insisted that this patient _____ seriously ill and he _____ on.A.should be,should be operatedB.should have been; had been operatedC.had been; should operateD.was; should be operated15.I wish my husband _____ as well as _____.A.will dress; youB.be dressed; youC.dressed; youD.dress; you16.If we _____ hard in the past few years, things _____ so smoothly now.A.hadn't worked; had goneB.hadn't been working; wouldn't be goingC.didn't work; weren't goingD.hadn't worked; would have gone17.I _____ each of the group leaders immediately work out a practical plan of study.A.hopeB.expectC.wishD.suggest18.Without the air to hold some of the sun's heat. The earth at night _____, too cold for us to live.A.would be freezing coldB.can freeze coldlyC.will be freezing coldlyD.would be frozen cold19.--- _____ you booked the tickets in advance, we would have left for Italy.---If so, we _____ the ball and failed to see a lot of interesting people there.A.had; should missB.should; might have missedC.should; had missedD.had; would have missed20.I am not free today. If I _____ free today, I _____ and visit some of my friends.A.am; will goB.were; would goC.shall be; may goD.be; must go21.It is strange that she _____ so upset.A.isB.will beC.becameD.be22.You have been working on this morning. It's time you _____.A.have a restB.will have a restC.had a restD.might have a rest23.But for your help, I _____.A.should not have succeededB.had not succeededC.were to succeedD.have not succeeded24.If only the weather _____ fine!A.beB.isC.wasD.were25.--- I won't go climbing the mountain this afternoon because I want to have a rest. --- _____ change yourmind,give me acall.A.Might youB.Should youC.Were youD.Would you26.What the workers insisted on was that they _____ more pay.A.should giveB.be givenC.would be givenD.were given27. _____ I _____ more money with me that day, I _____ you some.A.Did; have; could lendB.Have; had; would lendC.had; have; would have lentD.Had; had; would have lent28.It is necessary that all the young trees _____ more water.A.be givenB.must be givenC.will be givenD.will have been given29.It is demanded that we _____ there on foot.A.not to goB.don't goC.won't goD.not go30.John's pale face suggested that he _____ ill, and his parents suggested that he _____ a medical examination.A.be; should haveB.was; haveC.should be; hadD.was; has31.If my lawyer _____ here last Saturday, he _____ me from going.A.had been; would have preventedB.had been; would preventC.were; would preventD.were; would have prevented32.If Joe _____ in your position, he wouldn't be different.A.had beenB.wereC.isD.would be33.We had time,we _____ another try.A.are going to beB.would haveC.should have hadD.had34.If the sun _____ in the west, my life wouldn't be different.A.were to riseB.risesC.had risenD.has risen35.Give more time and money,we _____ better than what it is.A.didB.had doneC.would have doneD.would do36.I think it is high time that the children _____ to school.A.goB.will goC.wentD.are going37.Mr.Dean _____ a professor today if he had studied in a university.A.will beB.could beC.isD.had been38.Tom would bring you what you've been expecting if he _____ here tomorrow.esB.would comeC.will comeD.should come39.My grandma would have died if the doctor _____ in time.A.should comeB.would comeC.hadn't comeD.has no been40.If you _____ hard in the past few months, your lessons wouldn't be going so smoothly now.A.hadn't been studyingB.haven't studiedC.didn't studyD.wouldn't study41.The teacher demanded that the students _____ late for class.A.are notB.will not beC.shouldn't beD.wouldn't be42.Even though my friend was very busy, he _____ me more help.A.might have givenB.may have givenC.might giveD.may give43.It was ordered that no smoking _____ in the library.A.should allowB.be allowedC.will be allowedD.is allowed44.Without your encouragement and support, I _____.A.would not succeedB.would not have succeededC.should not succeededD.would have succeeded45.The boss required that Amy _____ at the company by eight.A.isB.would beC.beD.will be46.It's high time that we _____.A.should startB.startC.would startD.will start47.Betty wished that she _____ Mary about the bad news.A.didn't tellB.hadn't toldC.hasn't toldD.doesn't tell48.I'd rather you just _____ in bed and _____ anything for at least three weeks.A.stayed; didB.would stay; didn't doC.stayed; didn't doD.stay; don't do49.But for air and water, there _____ no life on the earth.A.will beB.isC.would beD.has been50.Take care in case you _____ cold.A.caughtB.should catchC.would catchD.catching51.My suggestion is that a few persons _____ to help us.A.will be sentB.sentC.are sentD.be sent52.--- If he _____, he _____ that food.--- Luckily he was sent to the hospital immediately.A.was warned; would not takeB.had been warned; wouldn't have takenC.would be warned; hadn't takenD.would have been warned; hadn't taken53. _____ anyone call, please take a message.A.IfB.ShouldC.WouldD.Will54.If only we _____ a phone! I'm tired of queuing outside the public phone box.A.hadB.haveC.would haveD.should have55.She looks as if she _____ mad.A.beB.would beC.wereD.should be56.If the dog hadn't woken us we _____ the fire and it _____ the house next door.A.hadn't noticed; had spread toB.wouldn't have noticed; might have spread toC.wouldn't notice; would have spread toD.didn't; notice; spread to57.I wish I _____ to talk this over with Mr. Zhang when he was here last night.A.had been ableB.should be ableC.have been ableD.were able58.If you were to do it, the result _____ different.A.will beB.would beC.should beD.would have been59. _____ today, he would get there by Saturday.A.If he leavesB.Was he leavingC.Would he leaveD.Were he to leave60.It was a lovely day yesterday. I wish I _____ at the seaside then.A.wereB.will beC.should beD.should have been61.It is a great pity that he _____ so careless.A.wasB.will beC.should beD.can be62.Even if I _____ with you then, I _____ much for you.A.would be; would not doB.were; should not have doneC.had been; would not doD.had been; should not have done63. _____, I would not refuse his invitation.A.Were I youB.If I should be youC.If I was youD.If I had been you64.The whole family greeted me as though I _____ a member of the family.A.amB.wereC.wouldD.should be65. _____, man could not live at all.A.He had been hereB.Here he had beenC.Been here he hadD.Had he been here66. _____, man could not live at all.A.Were it not for the sunB.If it was for the sunC.Had it not been for the sunD.If it shouldn't be for the sun67.Their suggestion that she _____ till next week is reasonable.A.waitB.are waitingC.will waitD.would wait68.If there were no subjunctive mood, English _____ much easier.A.will beB.would have beenC.could have beenD.would be69.If she had worked harder, she _____.A.would succeedB.had succeededC.should succeedD.would have succeeded70.-- The experiment had failed.---I suggest you _____ again.A.tryB.tryingC.will tryD.would try71.When a pencil is partly in a glass of water, it looks as if it _____.A.breaksB.had brokenC.were brokenD.had been broken72.We _____ the work on time without your help.A.hadn't had finishedB.didn't have finishedC.can't have finishedD.couldn't have finished73.If only I _____ as young as you are!A.beB.amC.wereD.being74.Should it rain, the crops _____.A.will be savedB.would be savedC.had been savedD.would have been saved75.It is important that we _____ wild animals.A.will protectB.should protectC.shall protectD.are protecting76.He is not a pilot, but he _____ he _____.A.wishes; wasB.wants; wasC.wants; wereD.wishes; were77.Look at the clock! It's time _____ home.A.we goB.we wentC.we are goingD.for us go78.They talked as if they _____ friends for years.A.areB.wereC.have beenD.had been79.I _____ the exam, but I failed.A.expected to have passedB.expected to passC.expect to passD.expect to have passed80.If you had taken your medicine yesterday, you _____ well now.A.would have beenB.should beC.would beD.will be81.If you _____ harder. You _____ tomorrow's exam.A.studied; will passB.studied; should have passedC.had studied; would passD.had studied; would have passed82.He ordered the work _____ started at once.A.beB.wasC.would beD.were83.You _____ ten minutes ago, but you didn't.eB.should comeC.would have comeD.should have come84.--- _____ you mind my opening the window?---Not at all.A.WouldB.WillC.ShallD.Should85.He insisted that we all _____ in his office at three o'clock.A.shall beB.beC.to beD.would be86.It is strange that he _____ such a mistake.A.have madeB.madeC.has madeD.makes87.Tom, you are too lazy! This job _____ three days ago.A.should finishB.must have finishedC.ought to have been finishedD.was about to finish88. ‘He is angry. So we _____ better be careful,’ she said.A.hadB.shouldC.wouldD.might89. _____ I in good health, I _____ with you.A.Were; will goB.Was; wentC.Was; should goD.Were; would go90.But for air and water, nothing _____.A.can liveB.will be able to liveC.could liveD.couldn't live91.If I were you, I _____ be worried.A.must notB.won'tC.shouldn'tD.shall not92.I wish I _____ well as she.A.could singB.can singC.singD.shall sing93.Without electricity, human life _____ quite different today.A.isB.will beC.would have beenD.would be94.I _____ study French than Japanese.A.should likeB.would ratherC.had betterD.would like to95.It's necessary that you _____ spoken English now and then.A.might practiseB.must practiseC.should practiseD.practised96.My suggestion is that a few more people _____ there to help me.A.be sentB.have sentC.sentD.should sent97.It is high time that all of you _____ to bed.A.goB.will goC.must goD.went98.Everything will go on as usual as if _____ happened.A.nothing hadB.anything hadn'tC.nothing wasD.anything was not99.The teacher demanded that the exam _____ before eleven.A.would be finishedB.must be finishedC.be finishedD.must be finished100.I'd rather you _____ at home all day today.A.stayB.stayedC.should stayD.had stay答案：1—5 ABDCC 6—10 DBCAC 11—15 BCADC 16—20 BDADB 21—25 DCADB 26—30 BDADB 31—35 ABBAC 36—40 CBDCA 41—45 CABBC 46—50 ABCCB 51—55 DBBAC 56—60 BABDD 61—65 CDABD 66—70 AADDA 71—75 CDCBB 76—80 DBDBA 81—85 CADAB 86—90 ACADC 91—95 CADBC 96—100 ADACB.。

高中英语虚拟语气练习题50题含答案解析1.If I were you, I _____ study harder.A.willB.wouldC.canD.could答案解析：B。

本题考查对现在情况的虚拟语气。

if 引导的条件句中，be 动词用were，主句用would/could/should/might+动词原形。

A 选项will 不是虚拟语气的用法；C 选项can 也不是虚拟语气；D 选项could 虽然是虚拟语气，但与本题的意思不太相符。

所以选B。

2.If he _____ more time, he would do better in the exam.A.haveB.hadC.hasD.would have答案解析：B。

对现在情况的虚拟，if 条件句中用过去式，主句用would/could/should/might+动词原形。

A 选项have 不是过去式；C 选项has 是一般现在时；D 选项would have 不是条件句中的用法。

所以选B。

3.If I _____ a bird, I could fly freely.A.amB.wereC.wasD.be答案解析：B。

虚拟语气中，be 动词统一用were。

A 选项am 是一般现在时；C 选项was 一般过去时，但虚拟语气不用was；D 选项be 不是完整的动词形式。

所以选B。

4.If she _____ taller, she could play basketball better.A.isB.wasC.wereD.be答案解析：C。

对现在情况的虚拟，be 动词用were。

A 选项is 一般现在时；B 选项was 不是虚拟语气的正确用法；D 选项be 不是完整的动词形式。

所以选C。

5.If they _____ more careful, they wouldn't make so many mistakes.A.wereB.areC.wasD.be答案解析：A。

高中英语虚拟语气练习题30题(带答案)1. If I ______ (be) you, I would study harder for the exam.A. amB. wasC. wereD. be答案：C。

解析：这是一个与现在事实相反的虚拟语气句子。

在虚拟语气中，be动词不管主语是什么人称，一律用were。

A选项am是一般现在时的形式，不符合虚拟语气语法；B选项was虽然是be的过去式，但在虚拟语气中不用于这种情况；D选项be是原形，也不符合语法规则。

2. If he had known the truth, he ______ (not make) such a mistake.A. would not makeB. will not makeC. would not have madeD. should not make答案：C。

解析：这是与过去事实相反的虚拟语气。

从句用had + 过去分词（had known），主句要用would/should/could/might + have + 过去分词。

A选项would not make是与现在事实相反的主句形式；B选项will not make是一般将来时，不符合虚拟语气；D选项should not make也不是与过去事实相反的虚拟语气主句形式。

3. If it ______ (rain) tomorrow, we would cancel the picnic.A. rainsB. rainedC. will rainD. should rain答案：D。

解析：这是与将来事实相反的虚拟语气。

在这种情况下，从句可以用should + 动词原形，或者were to + 动词原形，或者一般过去时（这里的一般过去时表示的是一种假设的将来情况）。

A选项rains是一般现在时，用于真实条件句；B选项rained虽然是过去式，但在这里如果单独用过去式表达将来不太准确；C选项will rain是一般将来时，不符合虚拟语气语法。

高中英语虚拟语气练习题30题含答案解析1.If I were you, I ____ study harder.A.willB.wouldC.shallD.should答案解析：B。

本句是对现在情况的虚拟，if 引导的条件句中用一般过去时were，主句用would+动词原形。

A 选项will 一般用于真实条件句；C 选项shall 通常与第一人称连用，但在虚拟语气中不这样用；D 选项should 虽然也可用于虚拟语气，但此处不符合语法规则。

2.If he had time now, he ____ play basketball with us.A.willB.wouldC.shallD.should答案解析：B。

对现在情况的虚拟，if 条件句用一般过去时had，主句用would+动词原形。

A 选项will 不对；C 选项shall 不符合；D 选项should 在这里不合适。

3.If she ____ taller, she could be a model.A.isB.wasD.be答案解析：C。

对现在情况虚拟，be 动词一律用were。

A 选项is 是真实情况的用法；B 选项was 用于单数主语，但虚拟语气中要用were；D 选项be 单独不能用在这里。

4.If I ____ a millionaire, I would travel around the world.A.amB.wasC.wereD.be答案解析：C。

对现在情况的虚拟，be 动词用were。

A 选项am 是真实情况；B 选项was 不对；D 选项be 单独不能用。

5.If they ____ more careful, they wouldn't make so many mistakes.A.areB.wereC.will beD.would be答案解析：B。

对现在情况虚拟，if 条件句用一般过去时were，主句用would+动词原形。

高三英语虚拟语气特殊用法练习题40题答案解析版1. If I had studied harder in history class, I ______ more about the causes of the Industrial Revolution now.A. knowB. would knowC. knewD. had known答案：B解析：这是一个错综时间条件句。

从句中“had studied”是对过去的虚拟，表示过去没有努力学习。

主句中有“now”，是对现在情况的虚拟，在虚拟语气中，对现在情况虚拟时，主句要用“would + 动词原形”结构。

所以这里应该选B，表示如果过去努力学习了，现在就会对工业革命的起因知道得更多。

2. Had he not been so brave during the war, his family ______ in great danger at that time.A. would beB. will beC. would have beenD. is答案：C解析：这是一个省略了if的虚拟条件句，正常语序是“If he had not been so brave during the war”，是对过去情况的虚拟。

在这种情况下，主句要用“would + have + 过去分词”结构，所以选C，表示如果他在战争中不那么勇敢，他的家人当时就会处于极大的危险之中。

3. If she were to start the project today, she ______ it in a completely different way considering the new technology available.A. will planB. would planC. plannedD. has planned答案：B解析：这是一个对将来情况虚拟的句子，“were to + 动词原形”是对将来虚拟的一种结构。

高一英语虚拟语气单选题20题(含答案)1.If I were you,I would study harder.A.would study harderB.will study harderC.study harderD.studied harder答案：A。

本题考查对现在情况的虚拟语气。

if 引导的条件状语从句中，谓语动词用过去式（be 动词用were），主句用would/could/should/might+动词原形。

选项B 是一般将来时，不符合虚拟语气结构；选项C 是一般现在时，也不符合；选项D 是一般过去时，同样不符合。

2.If he had more time,he would read more books.A.would read more booksB.will read more booksC.reads more booksD.read more books答案：A。

这也是对现在情况的虚拟语气。

if 条件句用过去式had，主句用would+动词原形。

选项B 一般将来时错误；选项C 一般现在时错误；选项D 少了would。

3.If she were a bird,she could fly everywhere.A.could fly everywhereB.can fly everywhereC.will fly everywhereD.flies everywhere答案：A。

对现在虚拟，if 从句用were，主句用could/would/should/might+动词原形。

选项B 一般现在时不对；选项C 一般将来时不对；选项D 一般现在时不对。

4.If I had a magic pen,I would draw beautiful pictures.A.would draw beautiful picturesB.will draw beautiful picturesC.draw beautiful picturesD.drew beautiful pictures答案：A。

高中英语虚拟语气练习题二．选择题C1. , .A. B. C. D.b2. I a .A. B. C. D.d3. . ,A. ; ’tB. ; ’tC. ; ’tD. ; ’t b4. ,A. B. C. D.c5. IA. B. C. D.6. a a ,A. B. C. D.7. I a ,A. ;B. ;C. ;D. ;8.A. B. C. D.9., IA. B. C. D.10. I , IA. B. C. D.11. ,A. B. C. D.12. ,A. ,B. ,C. ,D. ,13. ,A. B. C. D.14. ,A. . C. D.15. ,A. B. C. D.16. I . ,A. B. C. D.17. , .A. ,B. ,C. ,D. ,18. ,A. ,B. ,C. ,D. ’t ,19. ,A. B. C. D.20.A. ’tB. ’tC. ’tD. ’t21. ’s , ,A. B. C. D.22.A. B. C. D.23. aA. B. C. D.24.,A. I’dB. I’dC. I ’ tD. I’d25. IA. ’tB. ’tC. ’tD. ’t26. ,A. B. C. D. ’t27. IA. B. ’t C. ’t D. ’t28.A. B. C. D.29.A. B. C. D.30. aA. B. C. D.31.A. ,B. ,C. ,D. ,32. I a IA. B. C. ’t D. ’t33.A. B. C. D.34.A. B. C. D.35.A. B. C. D.36. I IA. B. C. D.37.A. B. C. D.38. IA. B. C. D.39.A. B. C. D.40.A. B. C. D.41.A. B. C. D.42. , . I ……’t “”, I . , !A. B. ’t C. D. ’t43. I . . I IA. ,B. ,C. ,D. ,44. I I ! IA. B. ’t C. D. ’t45. I’t .A. B. C. D.46. ’sA. ,B. ,C. ,D. ,47. ,A. B. C. D.48. .A. ,B. ,C. ,D. ,49.A. B. C. D.50. a .A. B. C. D.51. ,A. B. C. D.52. aA. B. C. D.53. IA. B. C. D.54. , I a , I IA. B. C. D.55.A. B. C. D.56. I . ,A. B. C. D.57. ,A. B. C. D.58. ,A. ,B. ,C. ,D. ,答案C BD B C C C B A A D A B A C D B C D AD C C B A C B B A B D C C A B B D B A AC D C B C D D B C D B B A A A C D C虚拟语气在条件状语从句中的应用【经典例题】1. , .A. ;B. ;C. ;D. ;2. I , I .A. ’t B ’tC. ’tD. ’t3.— , .A. ;B. ;C. ;D. ;4. I ’t . , .A. B. C. D.【答案与解析】1．A．本题考查虚拟语气。

高一英语虚拟语气运用练习题50题答案解析版1. If I ______ a millionaire, I would buy a big house for my parents.A. amB. wasC. wereD. be答案解析：C。

在虚拟条件句中，表示与现在事实相反的假设，be动词一律用were，不管主语是第几人称。

这里说如果我是百万富翁，这是与现在事实相反的假设，所以要用were，而不是am（A选项）；was虽然在口语中也有人用，但在正式语法中不符合要求（（B选项）；be（D选项）形式错误。

2. If he ______ more time, he would have finished the book yesterday.A. hasB. hadC. haveD. would have答案解析：B。

这是一个与过去事实相反的虚拟条件句。

在这种情况下，if从句要用过去完成时，即had + 过去分词。

这里表示如果他当时有更多时间，他昨天就能读完这本书，实际情况是他没有足够时间，所以要用had（B选项）。

has（A选项）是一般现在时；have （C选项）形式错误；would have（D选项）用于主句表示与过去事实相反的结果，而不是从句。

3. If it ______ rain tomorrow, we would go for a picnic.A. doesn'tB. didn'tC. won'tD. wouldn't答案解析：B。

这是一个与将来事实相反的虚拟条件句。

在这种情况下，if从句有三种形式：动词过去式、should + 动词原形、were to + 动词原形。

这里用动词过去式表示如果明天不下雨，我们就去野餐，实际上明天可能会下雨，所以用didn't（B选项）。

doesn't（A选项）用于一般现在时的否定；won't（（C选项）用于一般将来时的否定；wouldn't（D选项）用于虚拟语气的主句中。