情态动词have done表推测一览表

1、 “情态动词+have done”表推测一览表情态动词+ have done用法例句must have done一定已经做了They must have finished their work.cant have done不可能已经做了They cant have finished their workcould have done可能已经做了或本来可能做但未做You could have used my computer because I didnt use it.may have done也许已经做了They may have finished their work.might have

2、 done也许已经做了或本来可以做但未做You might have used my computer because I didnt use it.Should/ought to have done本来该做但未做You Should have studied hard.need not have done本来不必做但做了You need not have gone out.would rather have done过去宁愿做但未做I would rather not have gone there.would like to have done过去想做但未做I would like to

3、have seen the film.had better have done当时最好做了某事Youd better have gone there.“情态动词+be doing”表推测一览表情态动词+ be doing用法例句must be doing一定正在做They must be watching TV now.cant be doing不可能正在做They cant be watching TV now.May/might be doing也许正在做They may be watching TV now.口诀：“情动”加上have done,推测事情已经干； “情动”加上be doi

4、ng,推测事情在进行；情态动词+have done表推测一、must have done 一定已经做了。They must have finished their work.他们一定做了他们的工作。二、1、Can have done.可能已经做了。2、Cant have done.不可能已经做了。They can have finished /homework so quickly.他们可能很快完成他们的工作。They cann have finished /homework so quickly.他们不可能很快完成他们的工作。They can have gone to bed /since

5、/the door is closed.门关着，他们可能已经睡着了。 完成时态+since三、1、Could have done.可能已经做过。（对过去事情的推测）2、Couldnt have done. 不可能已经做过。You could have used my computer because I didnt use it.你可能使用过我的游戏机。因为我不能使用它。you couldnt have used my computer.你不可能使用过我的游戏机。3、Could have done表过去虚拟语气，过去表本来会做而未做。含责备，遗憾的语气。It was so fine yeste

6、rday, you could have come out for a walk.（对过去的虚拟语气）昨天天气好,你本来可以出来散散步的。（事实上没有散步， 对过去本来会做而没有做。）4、would have done.表示虚拟语气，本来完全可以做，而没有做。I would have come /to help /you with the work yesterday （to do）/but I was too busy.昨天我本想帮你做工作的，但我太忙了。（遗憾的语气）四、should have done.表示虚拟语气，本应该做而没有做。should=ought to 应该1、 Should

7、nt have done.本不应该做。（事实上做了）He shouldnt have swum /in the lake /alone.他本不应该独自一人在湖里游泳。（事实上已经游泳了，责备的语气）2、you should have studied hard.你本来应该学习努力。（事实上没有做到）五、neednt have done.表示虚拟语气。本来不必做，但做了。“多此一举”1、You neednt have watered /the flowers.你本来不需要给花浇水。六、will /shall have done.表示将来完成时，不表示推测，也不表示虚拟。七、may have don

8、e.也许已经做了。They may have finished homework.他们也许已经完成作业。You may have read the book.他也许已经读过书。八、might have done.也许已经做过，本来做但未做。（虚拟语气）They might have won the match.他们本来可以赢得这场比赛。（事实上没有赢）I might have passed the exam.我本来可以通过考试。（事实上没有通过）（虚拟语气）九、neednt have done.本来不必做但做了。（虚拟语气）You need not have gone out.你本来不必出去。

9、（事实上出去了）十、would rather have done.过去宁愿做但未做。（对过去的虚拟）I would rather you paid the money yourself.我宁愿你自己付钱，AA制。 I would rather not have gone /there.我宁愿没有去过哪儿。 I would rather do it today.我宁愿今天做。十一、would like to have done.过去想做但未做。（虚拟语气，过去的虚拟）I would like to have seen /the film.我过去想看场电影。（事实上没有看）十二、had bette

10、r have done.当时最好做了某事。Youd better have gone /there.你当时最好去哪儿。（事实上没有去）You had better not go dancing tonight.你最好今天晚上不去跳舞。情态动词+be going.表推测：Must be doing.一定正在做They must be watching TV nowCant be doing.不可能正在做They cant be watching TV nowMay/might be doing.也许正在做They may be watching TV now连词other wise, or, b

11、ut与with, whithout, but, if only 否则 但是 有 没有 但是 只要及其in case/for fear that/lest引导的从句，要用虚拟语气。 以免 以免 免With you help, we might finish the work earlier.有你的帮助，我或许能早点完成工作。Whithout water, there would be no life.没有水，就没有生物。条件状语从句中的虚拟语气：条件句分为真实条件句和虚拟条件句两种，真实条件句用陈述语气，虚拟条件句用虚拟语气。（虚拟条件句是虚拟语气的重点）虚拟条件句关键是要熟练掌握以下三大公式：

12、三个相反从句主句与现在事实相反If sb did/wereSb would/should/could/might do与过去事实相反If sb had doneSb would/should/could/might have done/have been与将来事实相反If sb did/wereIf sb were to doIf sb should doSb would/should/could/might do1、宾语从句中的虚拟语气：有三种情况。一是在动词insist(坚持)，order（命令），command(命令)，suggest（建议），advise（建议）。Recommend（建

13、议，推荐），require（要求）,request（请求），demand（要求），desire（要求，愿望），等动词后面的宾语从句中一般用虚拟语气，其结构为“主语+should+动词原形”，其中should可以省略。把以上10个动词简称为：一个“坚持”，两个“命令”，三个“建议”，四个“要求”。二是动词wish之后接宾语从句一定要用虚拟语气。从句的时态是：1、与过去事实相反用had done/had been,2、与现在事实相反用did或were,3、与将来事实相反用“would/might/could/should+动词原形”。注意：wish在简单句中并非表示的是虚拟语气，如：wish yo

14、u success.祝你成功。三是在would rather的宾语从句中，也要使用虚拟语气，其从句中谓语动词的时态用一般过去时。如：I would rather you didnt hear what I said. 我宁愿你没有听到我说的话。2、主语从句中的虚拟语气少数“it is+形容词+that+主语+should+动词原形”，其中should同样可以省略。常见形容词有：important,necessary,strange,unusual,curious,remarkable,surprising,desirable,natural等。3、定语从句中的虚拟语气“it is(high/a

15、bout) time that+主语+动词的过去式，或者是“should+动词原形”。Time是先行词，that是引导词，其意思是“早该做什么事了”如：1、It is high time that you went to school.=it is high time that you should go to school.你该上学了。2、It is about time that you picked up your daughter at school.= It is about time that you should pick up your daughter at school.你

16、该去学校接你女儿了。熟练掌握强调句型：句型结构是：it is/was+被强调部分+that/who+句子原有部分。在强调句型中，强调人时，一般用who,也可用that,但强调时间，地点等时只能用that,不能用when,where等。1、 强调主语2、 强调地点状语3、 强调时间状语4、 强调宾语。not until的三大句型：例：妈妈回家之后我才睡觉。正常 I did not go to bed until my mother come back home.强调 It was not until my mother came back home that I went to bed.倒装 N

17、ot until my mother came back home did I go to bed.怎样识别not until是强调句还是倒装句呢？很简单，如果否定词not在句首，就是倒装句，如果it在句首，就是强调句。it的10大句型1、It was for the first time that I wrote to a foreign pen friend.这确实是我第一次给一个外国笔友写信。这是强调句型。还原为：I wrote to a foreign pen friend for the first time.2、It is the first time that I have wr

18、itten to a foreign pen friend. 这是我第一次给一个外国笔友写信这是定语从句，that之后的时态要用现在完成时态。3、It was eight when the class began.8点钟开始上课。这是时间状语从句，强调句型：It was at eight that the class began.4、It is possible that I will enter this key university.我上这所重点大学是可能的。这是主语从句。It是形式主语。that I will enter this key university是真正主语。还原成：That

19、 I will enter this key university is possible.5、It is/has been three years since he got married.他结婚（成家）已经三年了。It is/has been some time since sb did(短暂性动词)sth.意为“自从某人干某事已经有多长时间”例如：It is/has been three years since he worked here.他不在这儿工作已经三年了。6、It will be one year before she finishes middle school.再有一年时

20、间她就中学毕业了。It is/was/ will be some time before意为“过多长时间后再干什么”。7、It is high time we went to school.我们上学的时间到了。这时定语从句，在It is（high）time that句型中，that之后谓语动词的时态要用一般过去时或“should+动词原形”，属于虚拟语气。8、It is said that a new factory will be built nearby my hometown.据说一家新工厂将见在我家乡附近。这时主语从句。it is+过去分词+that.。类似的句型还有：It is re

21、ported that/ It is known that/ It is thought that/ It is suggested that/ It is believed that/ It is hoped that等。9、It looks as if it is going to snow.看起来要下雪了。这时表语从句，类似的句型还有：It seems to sb that/ It (so)happened that/ It appears to sb that(=as if)等。10、It is necessary that we should master a foreign lan

22、guage.我们掌握一门外语是必需的。这是主语从句，在“It is+少数形容词+that sb should do ”这种句型中，it同样是形式主语，that之后从句的谓语动词是“should+动词原形”，其中should可以省略。这样的形容词有necessary/important/unusual/strange/natural等。情态动词表推测（排名次）一、1、must一定，必须。语气强硬。 must=have to 不得不，适用于各种时态。例句：1、Its very late now, must you watch TV?(must非要，偏要) You must go=you have

23、to go你必须走。 2、must/neednt,用must提问，用neednt否定回答Must I be here/at eight tomorrow morning?No ,you neednt 或者no you cant. 不，你不必3、must+be表推测，一定，一定是。 You must be tired.你一定是累了。 You must see her.你一定要见她。 She must be playing piano.她一定是在弹钢琴。4、need/must.用need提问，肯定回答，yes ,you must.need I do anything for you.我需要为你做任

24、何是吗。yes, you must / No,you neednt 是的，你一定的做。不，你不必。二、can /be able to.能够，能力。适用于现在时、过去时。表推测可能。 be able to适用于各种时态，表努力实现的能力。He /has been able to /speak English since /he was a child.他自从小时候起，他就会说英语。此处be able to用于完成时，而can不能。Could表委婉的语气。Could you help me?你能帮我吗？三、may /might 也许，可能。表不太确定，语气较弱。may, I come in.No,

25、 you mustnt /cant / yes, you may.用may提问，否定回答。No ,you mustnt /No cant.May /might as well.“不妨，最好”与had better相近。You /might as well /go home now.你最好现在回家。 最好四、shall /will, will用于各种人称，shall用于第一人称单复数I ,we Shall用于二、三人称，表示命令，威胁，允诺，决心。Study hard and you shall get arise,said the teacher.(表示允诺)“努力学习你将得到奖励”老师说。

26、（二、三人称）Shall we come to see you?要不要我们来看你？五、should /ought to应该。 Ought to表责任，义务 法律 Should建议、劝告1、you should study /English hard.你应该努力学习英语。 应该Should竟然You should play computer golme,你竟然玩游戏。Should she do /such a thing?她竟然做这种事情？How /should I know?我竟然不知道？Why /should you talk like that.你为什么这样说话。dare /need既是情态动词，又是实义动词。you /neednt go /there today, need you.(情态动词，反意疑问句)you/need to go /there today, dont you.(行为动词，反意疑问句) need to do sthH