英语助动词和情态动词及练习

1、英语助动词和情态动词及练习一、 概述不同的时态（一般式、进形式、完成式、将来式），不同的语态（主动、被动），不同的语气（祈使、陈述、虚拟），不同的结构（肯定、否定、疑问），以及说话者本身的态度或命令、请求、愿望、可能等，所有这些都要借助于助动词和情态动词表达出来。助动词一般没有词意，不能单独作谓语动词，除非省略句中。他们只参加时态、语态、语气或否定、疑问结构。情态动词有词义，可以用来表示说话者的语气和态度。主要的助动词和情态动词如下表：助动词情态动词be(am, is, are, was, were, being, beencan, could, be able tohave(has, had

2、 , havingmay mightshall, will(should, wouldshall, should, （ought to）will, would do (does, diddare, need, must二、助动词助动词一般没有词意，不能单独作谓语动词。其作用在于帮助构成各种时态、语态、否定、疑问等。1、助动词be（am, is, are, was, were, being, been）的用法（1） be后跟现在分词构成进行时态。Who is playing the violin?谁在拉小提琴？She was reading a book then.那时她正在读书。（2）be后跟

3、过去分词构成被动语态。He was asked to do the work.有人要他干这件工作。You are invited to attend the meetintg.有人邀请你参加会议。（3）be 后跟不定式作谓语，有如下几种情况：表示计划、安排将要发生的事。Who are we to meet?我们要见谁呀？I'm to have supper with John this afternoon.今天下午我要与约翰一起吃晚饭。表示指示、命令，否定式表禁止。You are to see the headmaster today.今天你必须去见校长。You are not to

4、enter the room without permission.未经允许你不能进入房间。表示义务、责任等，同should。You are to be back before 5.你得在5点钟以前回来。What is to be done?该干什么。表示可能性，与情态动词may, can同义。Such books are to be found in any library.这种书任何图书馆都有。Not a sound was to be heard.一点声响也没有。表示后来发生的事，可以用来表示命运或注定They say good-bye, little knowing that they

5、 were never to meet again.他们告别了，没想到再也不能相见了。He was to regret the decision.他有一天会后悔做出这一决定的。用于习语Where am I to go? 我该向何处去？What am I to do? 我该怎么办？2、助动词have(has, had, having的用法（1）助动词have可以构成完成时或完成进行时He has been a doctor for 10 years.他当医生十年了。This is the place I have been longing to visit.这就是我一直渴望参观的地方。（2）和不

6、定式构成谓语，表示客观上不得不做的事情。We've missed the train. We'll have to wait for another one.我们己经误了火车，我们只能等下一列。-Do we have to start work?我们得立刻工作吗？-No. We don't have to.不，不必了。3、do(does, did 的用法（1）构成疑问句或否定句How did you know about it?你是怎样知道这件事的。He does not smoke. 他不抽烟。（2）加强语气。He did tell that.他的确告诉了此事。Do

7、come and see us.一定来看我们。（3）代替前面刚出现的动词，避免重复。-You like popular music, don't you?你喜欢流行音乐，是吧？-Yes , I do.是的，我喜欢。He speaks French as fluently as she does.他讲法语和她讲的一样流利。（4）用于倒装句中。Never did he pay attention to my words.他从不注意我的话。Only then did I understand the importance of English.只是那时，我才了解到英语的重要性。（5）构成否定

8、的祈使句。Don't be so careless.不要那么粗心。Do not hesitate to come for help.只管来求助。4、shall(should和will(would 的用法（1）shall(should用于第一人称的将来时中，单纯表示来I shall think it over.我要好好考虑一下。When shall I see you again?我何时再见到你？I rang up to tell her that I should leave for London. 我打电话告诉她我要去伦敦。（2）will用于第二、第三人称的将来时态中，在现代英语中可

9、以用于所有人称He will be 30 next month. 他下月将是30岁。You will have an English test tomorrow.明天你有英语小测验。He wanted to know when you would finish the writing.他想知道你何时完成写作。三、情态动词1、情态动词的特征情态动词表示说话人对某一动作或状态的态度，认为“可能、应当、必要”等等，但本身意义不完全，不能单独作谓语，必须和其他动词一起构成谓语。除ought, used, have后跟不定式外，其他情态动词一律跟动词原形。情态动词主要有：can/could, may/m

10、ight, must, ought to, used to, need, dare, shall/should, will/would, have to等。2、情态动词的变化形式（1）没有人称和数的变化。I can /we can/ you can he can/she can/they can/it canJohnny, you mustnt play with the knife, you may hurt yourself.约翰，你不能玩刀，那可能会伤着你。A left luggage office is a place where bags can be left for a shor

11、t time, especially at a railway station. 行李寄存处特别是在火车站短时间存放包的地方。He ought to know her address.他该知道她的地址。（2）大部分情态动词有过去式：can-could may-might need-needed dare-dared shall-should will-would Is John coming by train? 约翰坐火车来吗？ He should, but he may not. He likes driving his car.应该是，他有可能不乘坐火车。他喜欢开车。- Are you c

12、oming to Jeff's party? 你来参加Jeff的聚会吗？- I'm not sure. I might go to the concert instead. 我不敢肯定，我可能去参加音乐会。（3）少部分情态动词没过去式或者说过去式与原形相同，used to 只有过去式形式。must-must(had to ought to -ought to I used to go there.我(以前常到那里去。You must be tired after your long journey. 你走了这么远的路，一定很累。（4）大多数情态动词后面还可跟动词的进行时、完成时

13、和被动式形式：can/may/must+ be doing/have done/be doneshould/would/might+be doing/have done/be doneHe must have earned a large sum of money.他一定是挣了一笔巨款。You mustnt always be talking so much.你不能总是说起来没完没了。3、否定式和疑问式情态动词的否定式和疑问式同助动词。否定式是在情态动词后加not；疑问式是将情态动词提前到主语的前面。情态动词否定式简略式canmaymustcouldmightneeddareshallwill

14、shouldwouldoughtusedcan notmay notmust notcould notmight notneed notdare notshall notwill notshould notwould notought notused notcan'tmayn'tmustn'tcouldn'tmightn'tneedn'tdaren'tshan'twon'tshouldn'twouldn'toughtn't tousen't to-Will you stay for lunc

15、h? 你留下来吃午饭好吗？ -Sorry, I cant. My brother is coming to see me. 对不起，我不能（留下来吃午饭），我兄弟要来看我。May I ask you a question?我可以问你一个问题吗？I was really anxious about you. You shouldnt have left home without a word. 你真急死我了。你不该一句话也不说就离开家。注意：have to 的疑问和否定是借助于do来构成。Do you have to go out today?今天你得出去吗？He doesnt have to

16、go.他没必要去。四、情态动词的基本用法1、can和could（1） 表能力意为“能够会”，表示体力或脑力等方面的能力Some of us can use the computer now , but we couldn't ten years ago.现在我们一些人能用计算机了，但十年前我们不能。Can you ride a bike?你能骑自行车吗？What can I do for you?我能为你做点什么？I could run faster then. 我那时能跑得更快一些。当can和could表示能力时，有时可以用be able to替换，could表过去，can表现在，有

17、时也可表将来，但不能与will, shall等助动词连用；be able to可以用于将来、完成等时态。She hasn't been able to come to school for three days.她已经三天没能来上学了。With his help, we shall be able to build the house.在他的帮助下，我们将能够建造房屋了。当我们要强调过去确实使用了某种能力时，要用was（were）able to，而不用could。was able to 表示“设法干成某事”，即succeed in doing sth.或manage to do sth

18、.而could只表示“具备某种能力”。He is such a good swimmer that he was able to save the two boys from drowning the other day.他是一位游泳健将，因此前些日子他救上了两名溺水男孩。The fire spread through the hotel very quickly but everyone was able to get out. 虽然大火蔓延很快，使旅馆烧起来，但大家还是逃了出来。（2）表可能性I thought the story could not be true我认为这个故事不可能是真

19、的。Anybody can make mistakes.人都会犯错误。（3）表许可（常用于口语中）。Can/Could I go now?我可以走了吗？He said I could use the computer.他说我可以用计算机。Father said we could go to the concert.父亲说我们可以去参加音乐会。-Could I borrow your dictionary? 你把字典借给我可以吗？-Yes, of course you can. 当然可以。（4）表惊异怀疑、不相信等态度主要用于否定句、疑问句和感叹句中，表惊异怀疑、不相信等态度。Where can

20、/could they be now?他们现在能在哪儿呢？What can he mean?他会是什么意思？如果跟完成时，则表示对过去发生的事的怀疑和不肯定。could比can更加不肯定。Can he have left already?他会是走了吗？Could she have forgotten my address?她会把我的地址忘了？It couldn't have been Xiao Wang. He has gone to the factory.那不可能是小王，他去了工厂。-There were already five people in the car but the

21、y managed to take me as well. 车上本来已经有五人，但他们还是设法把我也带上. -It couldn't have been a comfortable journey.那次旅行不可能舒服。注意：当说话的人对一件事表示肯定的判断时用情态动词must，当说话的人对一件事持否定的态度，这种判断用情态动词cant或couldnt。The man with glasses must be Tom's father. They look alike. 戴眼镜的那个人肯定是汤姆的父亲。他们看起来很像。Jack can't be in the classr

22、oom. I saw him on the playground just a moment ago. 杰克不可能在教室里。我刚才看见他在操场上。“could+完成时”，有时表示“过去本能够完成的事而没完成”。You could have done the work better.你本来能做得更好些。（事实并非如此）You could have caught the early train.你本来能赶上早班火车。（事实上没有）-I stayed at a hotel while in New York. 我在纽约住在一家旅馆。-Oh, did you? You could have staye

23、d with Barbara. 是吗？你本可与巴巴拉住在一起的。（5）表比较委婉客气地提出请求。这时could和can没有时间上的差别，只不过用could比用can显得更加委婉客气。Can you change a pound note for me , please?请你兑换一英镑零票给我好吗？Could you tell me the right time please?请你把准确的时间告诉我好吗？2、may和might（1）表示许可或征询对方许可。You may go now.现在你可走了。May I watch TV after supper?晚饭后我可以看电视吗？He said th

24、at I might use the telephone.他说我可以用电话。注意：征询许可时，might比may更恭敬有礼。may的否定形式为may not，但表示“不可以”、“阻止”等意思时常用must not(musn't代替may not。Might I have a word with you , please?我可以和你谈一谈吗？-May I take the book out of the reading-room? 我可以将这本书带出阅览室吗？-Yes , you may./No, you musn't./No, you may not./No, you'

25、d better not. 是的，可以/不，不行。（2）表可能性，有“或许、可能”之意might与may可以换用，但might表示较多的怀疑、更加不肯定、语气更委婉。He may/might be English.他可能是英国人。They may/might have a lot of work to do.他们可能有许多工作要做。Peter may come with us tonight, but he isn't very sure yet. 皮特今晚可能和我一起来，但他还没定。注意：may表可能一般不用于疑问句，在疑问句中通常用can/might,或者以be likely to

26、结构出现。Can it be true?这可能是真的吗？What can she be thinking of?她可能在想些什么？Might I make a suggestion?我可以提个建议吗？Is he likely to win the match?他有可能赢这场比赛吗？（3）"may/might+完成时"，表示对过去事情的推测，might比may更含蓄，委婉，或更加不肯定。Sorry, Im late. I might have turned off the alarm clock and gone back to sleep again. 对不起，我可能是把闹

27、钟关掉了又睡着了。She may/might have gone to the library.她可能到图书馆去了。She may/might have missed the plane.她也许没赶上飞机。（4）"might+完成时"表示过去本可以干的事而没干。You might have told me earlier!你本来可早点告诉我。（而没告诉，表责备）You might have been more careful.你本来可以多加小心。（而没有）巧记表“推测”的情态动词用法肯(can不肯？妹(may不问，妈妈(must肯定不否问。（5）用于表目的或让步状语从句中。

28、She was studying English so that she might read English books.她正在学习英语，以便能阅读英文书籍。He died in order that others might live. 他为了别人而牺牲了。（6）表祝愿（不能用might）。May all our dreams come true.愿我们梦想成真。May that day come soon.愿这一天早日到来。3、must和have to （1）must表示“必须”，“应该”。否定式must not(mustn't表示“不应该”，“不许可”，“不准”,“禁止”等。在

29、回答带有must的问句时，否定式常用need not(needn't或don't have to 表示“不必”，而不用must not (mustn't。The work must be finished as soon as possible.这件工作必须尽快完成。You mustn't speak like that.你不能那样说话。Must I be home before eight o'clock? 8点之前我必须回家吗？Yes, you must./No, you needn't./No, you don't have to.

30、 是的，必须回家。/不，不必了。（2）must表推测，一般只用于肯定句中，译成汉语“一定”，“必定”。There must be some mistakes.肯定有一些错误。You must be very tired.你一定很累了。如果表示对过去事情的推测，就用"must+完成时"。You must have left your umbrella in the theatre.你一定把雨伞丢在剧院里了。His car is still here. He must have gone by bus.他的车还在这里，他一定乘公共汽车走了。当must表推测之意时，其否定形式常用

31、can not而不用must not。He can't have been to your home. He doesn't know your address.他不可能到过你家，因为他不知道你的住址。What can he be doing at this time of night?夜晚都到这个时候了，他究竟在干什么呢?（3）must表必然性You must catch cold if you don't put on more clothes.如果你不多穿些衣服，必然感冒。All men must die.人固有一死。Truth must be out.真相总会大

32、白。（4）have to表示“必须”，“不得不”，在这个意义上与must很接近，但must表示的是说话人的主观看法，而have to 表示的却是客观需要。I have to go now.我得走了。（客观需要）I must go now.我必须走。（主观看法）You have to work hard to make a living.为了谋生你就得努力工作。（客观需要）You must do what I tell you.你必须按照我告诉你的去做。（主观要求）（5）have to 有更多的时态形式：现在时，过去时，将来时等，而must只有现在时形式。We had to be there a

33、t 8.我们得8点到那里。I shall have to go to school tomorrow.明天我得去上学了。（6）have to 不能代替表推测的must，但在虚拟条件句中用had had to+动词原形表示与过去相反的情况。You must be joking.你一定是在开玩笑。（不能用have to）If I had had to do the work, I should have done it in a different way.如果我不得不做这项工作，我会以不同的方式去做。（不能用must）If I had had to run the factory, I woul

34、d have had it run by able men.如果我得管理那家工厂的话，我就会让能人来管。（不能用must）4、ought to（1）ought没有人称或时态的变化，后跟带to的不定式。常译作“应该”，“应当”等，和should同义，只是口气稍重一些。其否定式为ought not to (oughtn't to ，疑问式为Ought I /you to?You ought to start at once你应该立刻出发。Such things ought not to be done.这种事不应该干。-Ought he to go? 他应该走了？-Yes, he ough

35、t to.是的，应该走了。（2）表可能性Mary ought to be home by now.玛丽这会儿该是到家了。There is a fine sunset. It ought to be a fine day tomorrow.今天有晚霞，明天应该是个好天。It ought to be a fine day tomorrow morning.明天旱晨大概是个好天气。（3）表示没有履行过去的义务时，用“ought to +完成时。You ought to have told me about this earlier.(But you didn't你本来应该早一点把此事告诉我。

36、（但没有）I ought to have written that letter yesterday.(But I didn't我本应该昨天写那封信。（但我没写）It ought to have been done long ago.这事早该做完的。5、used to used to只有一种存在形式,一般过去式。具体用法如下：（1）在肯定句中，表示现在己经不再发生，不复存在的过去的行为或存在的状态。He used to smoke 20 cigarettes a day.他过去每天抽20支烟。There used to be a building there.那里曾经有座大楼。（2）u

37、sed to 通常只能跟不定式，但偶尔也能跟进行时，意思一样。He used to be always making jokes.他过去总爱开玩笑。（3）在疑问句、否定句或强调句中，可以有两种形式：Used you to go to work by bike?Did you use to go to work by bike?你过去常骑车上班吗？He usedn't to smoke as much as he does now.He didn't use to smoke as much as he does now. 他过去不像现在抽这么多烟。I certainly use

38、d to play football, but it was a long time ago.I certainly did use to play football, but it was a long time ago.我过去的确常踢足球，但那是很久以前的事了。（4）在反意疑问句或简略回答中，也有两种形式：John used to be very fat, didn't he/usedn't he?约翰曾经很胖，是吗。Used you to live in Shanghai?你过去曾住在上海？Yes, I did/ I used to.是的。（5）used to 与woul

39、d的区别：情态动词used to 和would都可以表示过去的习惯性动作，但有下列不同点：used to 表示确定的过去时间，不需与确定的过去时间连用，而would一般与时间状语连用。used to 含有与现在相比较的意思，而would没有。He used to get up early.他过去常常早起。(现在不早起了The old man would go to the park every day to have morning exercises.那位老人以前每天都去公园晨练。（没有与现在相比较的意思）used to 指过去反复发生或持续发生的动作，而would仅指过去反复发生的动作，不

40、指持续发生的动作；另外，used to 既表动作还表状态，而would只表动作不表状态，因此下列句中的used to 不能用would代替。People used to think that the earth was flat.人们过去认为地球是平的。She used to be very nervous in the exam.她以前考试常常很紧张。used to 表客观事实，would则表示一种意愿。When he lived by the sea, he used to suffer diseases.他住在海边时，经常有病。（used to 不能换成would）There used

41、to be a small village here.这里曾经有一个小村庄。6、daredare作情态动词表示“敢”，主要用于否定句、疑问句和感叹句，无词形变化，单数第三人称不加-s。（1）通常用于否定句和疑问句，其用法同其他情态动词。She daren't even look out.她甚至不敢向外看。Dare you go to school by yourself?你敢独自一人去上学吗？How dare you say I am unfair?你怎么敢说我不公平!I dare not sleep in that room again.我再也不敢睡在那房间了。（2）dare在下列情

42、况下，也用于肯定句中。句子含有否定意义或疑问意义时。I hardly dare think of it.我简直不敢想这事。He asked me whether I dare swim across the river.他问我是否敢游过河。I wonder how he dared say that to the teacher.我不知道他怎么敢那样和老师说话。在简略答语中。You daren't climb that tree, dare you?你不敢爬那棵树，对吗？Yes , I dare. 不，我敢。状语从句中。I won't allow you to swim acr

43、oss the river, even if you dare do it.即使你敢，我也不愿你游过河去。（3）dare既表现在和将来，也表过去。Alice was afraid and dare not go. 艾丽丝害怕，不敢去。注意：从上下文看不出具体时间时，通常不用情态动词dare，而用实义动词的过去时。She dared to go.她敢去。She didn't dare(togo.她不敢去。7、need（1）表示 "必要;必须"，通常用于否定句和疑问句Need he work so hard? 他需要这么用功吗？You needn't worry

44、 about it. 你不必为此担忧。I hardly need say how much we missed you. 不必说我们多么的想念你。（2）在肯定句中，它被must或have to 取代。Need I come? 我需要来吗？Yes, you must/have to.需要。You needn't see him, but I must /have to.你不必去看他，但我必须去。（3）“need+一般式”，通常表现在和未来，有时也可指过去。She need not come. 她不必来。（现在或将来）We were told that we needn't do

45、that.我们被告知不必做那事。（过去）Need she go yesterday?她需要昨天走吗？（过去）如果从上下文看不出具体时间时，通常不用情态动词need表过去，而用实义动词need的过去时或had to表示。She didn't need to come.She didn't have to comeShe had not to come.她不必来。（4）“need+完成时”表示过去不必做而实际做了的事。You needn't have hurried.你本不必这么匆忙。Peter needn't have done it yesterday.彼得昨天

46、本不必做这件事。8、shall（1）用在疑问句中，用来征求对方意见或请求指示或向对方提出建议，用于第一、三人称。Shall I tell John about it? 咱们把这件事告诉John好吗？ No, you needn't. I've told him already. 你不必了。我已经把这件事告诉他了。Where shall I wait for you?我在哪里等你。Shall we start the meeting now?我们现在开会好吗？Shall those books be sent over to you at once?那些书立即给你送过来吗？（2）

47、用于第二、三人称，可表示说话者的一种决定、允许或威胁。If you work hard, you shall have a holiday on Sunday.如果你努力工作，星期天就可以休假。（允许）She shall do it, whether she wants or not.不管她愿意不愿意，她必须做这件事。（决定）He shall suffer for this.He shall pay you what he owes you.他必将自食其果，他欠的债一定得还。（威胁）9、should（1）表“劝告、建议”时，可译成“应该”，这时可用ought to替换。You should k

48、eep your promise.你应该遵守诺言。Young people should learn how to use computers. 年轻人应该学如何应用计算机。（2）表示委婉陈述自己的意见。I should think you are right.我想你是对的。I should advise you not to go now.我劝你现在别走。（3）表示惊异赞叹、忧虑、惋惜、欢欣、不满等情绪。Why should you think so?你为何这样想呢？（不满）It's strange that it should be so hot today.很奇怪，今天怎么这么热

49、。（惊奇）It's wonderful that you should have achieved so much in these years.这几年你们有了这样大的成绩，真了不起。（赞叹）（4）表推测意为“可能，该”，表示对现在情况、将来情况的推测。They should be home by now.他们现在应当到家了。The book you need should be in our library.你需要的那本书我们图书馆应该有。Its nearly seven oclock. Jack should be here at any moment.现在快要七点了，杰克随时会到

50、。-When can I come for the photos? I need them tomorrow afternoon. 我什么时候能取照片？明天下午要用。- They should be ready by 12:00.明天12点前应该能冲好。（5）“should+完成时”，在肯定句中，表示应完成而实际未完成的事情；如果用在否定句中，则表示发生了不应当发生的事件。I told Sally how to get here, but perhaps I should have written it out for her.我和萨丽说了怎样来这里，或许我应该给她写清楚。You should

51、 have stopped at the red light.你见了红灯本应该停车。（未停）You should not have gone back to work without the doctor's permission.你未经医生许可不应该回去工作的。（回去了）10、will（1）表意志、意愿、允诺，可用于多种人称。I will tell you all about it.我愿告诉你一切。（意愿）We'll help him if he asks us to.如果他让我们帮忙，我们一定会帮的。（表意志）Come whenever you will.你随时都可以来。（

52、允诺）If he will come into the hall, the meeting will begin soon.请到大厅来，会议快要开始了。If you will make another try, I shall do everything possible to help you.如果你愿意再试一次的话，我愿意尽一切可能帮助你。Say who will, nobody believes it.不管他说什么也没人相信。（2）用于第二、第三人称的疑问句中，表询问或请求。I'm going to the library. Will you go with me? 要去图书馆，

53、你愿与我一起去吗？（询问）Will you give him a message when you see him? 见到他时，请给他个信好吗？（请求）（3）用于第二、三人称表推测。That man with the book will be Mr. Smith的那个人可能是史密斯先生。You will remember the story I told you the other day.你大概还记得我那天给你们讲的故事。（4）有时表示一种习惯性动作，常用于第三人称。Fish will die out of water.鱼离开水就不能活。She will sit there for hour

54、s doing nothing.她往往会坐在那儿几小时，什么也不干。11、would（1）would是will的过去式，表示过去时间的意志、意愿、决心，用于各种人称。They said they would help us.他们说他们愿意帮助我们。I promised that I would do my best. 我承诺我决心尽最大努力。（2）would表示说话人的意愿或向对方提出请求，语气比will婉转，仍指现在时间。Would you like some bananas?你喜欢吃香蕉吗？I'd like to see your new bike.我希望看看你的新自行车。Woul

55、dn't it be better to leave tomorrow?明天离开是不是更好？（3）表示过去习惯发生的动作(与used to有区别，见used to。When he was there, he would go to that coffee shop at the corner after work every day. 他在那里时，他每天下班后都到拐角处那家咖啡店去。The old worker would often go to the park to play chess.那位老工人过去常去公园下棋。She would come to see me now and

56、then.她时常来看我。（4）表示推测。That would be his father.那大概是他父亲。You would be about 10 years old then.你那时大概10岁左右。12、had better(best+动词原形，would rather+ 动词原形+than +动词原形,would rather+虚拟式丛句had better(best+动词原形意为“最好”，否定形式had better not,疑问句把had放在主句前。这个结构用于现在时或一般将来时，通常用于所有人称。We'd better not invite him.我们最好不要邀请他。Yo

57、u'd better stay at hospital for another few days.你最好在医院再住几天。Better have the operation right now.你最好还是现在就动手术。Had he better set off at once? 他马上动身好吗？would rather意为“宁愿，宁可”，后接动词原形，否定式为would rather not, 疑问句把would放在主语前。Would ratherthan 意为“宁愿而不”，than后面接动词原形（不带to），would rather 后面接从句时要用虚拟式。Which would yo

58、u rather do, go to cinema or stay at home? 你是去看电影还是待在家里？He would rather die than surrender. 他宁死不投降。I would rather you hadnt lent her the bike the other day.我宁愿你前些日子不借给他自行车。I would rather he stayed at home.我宁愿他呆在家中。五、“情态动词+be doing”的用法1、推测或评论某动作是否正在进行Our teacher must be correcting our exam papers.我们的老师想必在批改试卷。He can't be working now.他不可能正在