情态助动词归纳.doc

17.1 情态意义表示法 英语动词，按其在构成动词词组所起的作用，分为主动词和助动词两大类。助动词又分为基本助动词、情态助动词和半助动词。情态助动词有十四个：may, might; can, could; will, would; shall, should; must, need, dare,dared， used to, ought to.情态助动词都表示情态意义，而且太多一词多义，在意义和用法上有不少交叉的地方。本节首先从语义角度对情态助动词的用法作一些比较说明，为便于比较，我们把一些语义相关的半助动词（如be able to, have to等）也结合在一起处理。1 . 表示“能力”和“可能”A.a) 表示“能力”（ability）,可用can, could, be able to. Can 既能表示现在的能力，也能表示将来的能力：You can make that.I cant do it by myself, but I can do it with Linda.He can do it now.You can do it later.b) 用can表示现在的“能力”，既可表示做某桩具体的事情的“能力”：I can swim.Is there anything I can do for you?c) 也可泛指一般的“能力”：I can ride a bike.He can play the violin.She can read that in an hour.d) can表示“能力”与be able to同义，在许多情况下可以交替使用：I can/am able to help her if I have got enough money.e) 尤其是将来的“能力”，通常用will/shall be able to 表示：He wont be able to get the job.f) 当然，要表示将来做某桩具体事情的能力也可用can：Can you do that?If I can, I will go to see her.g) 表示过去的“能力”，可用could和was/were able to，但在肯定句中，could所表示的“能力”仅是泛指过去的一般能力：I could ride a bike when I was young.A year ago I could still read without glasses.h) 如果要表示过去做某桩具体事情的“能力”，通常不用could，而用was/were able to（以及managed to）：He was able to translate the article without a dictionary.I was able to climb the hill before my leg hurt.i) 上述could与was/were able to用法上的区别仅是就肯定句而言；在否定句中却无此限制：could既可表示过去的一般能力，也可以表示过去做某桩具体事情的能力：He got so drunk that he couldnt/wasnt able to find the front door.I couldnt/wasnt able to play the piano when I was at school.B.a) 表示“可能”（possibility）,可用may, might, can, could. may/ might 表示“可能”，往往可以交替使用，从而比较婉转。may / might 既可以表示现在的可能，：It may/might be true.He may not/might not live near the theatre.He may/might be still waiting at the door.b) 也可表示将来的“可能”：He may/might leave tomorrow.He may not/might not leave next week.c) 在疑问句中表示“可能”，需用can而不用may：Where can he be?He may be in the office.Can they have missed the bus?Yes,they may have.d) 用may not表示“不可能”，重音通常落在助动词上：He may not go tomorrow.= it is possible that he will not go tomorrow.e) 如果重音落在否定词上，则意义有所改变，不是表示“不可能”，而是表示“不许可”：He may not go tomorrow.= I dont permit him to go tomorrow.f) 正因为在书面语中may not可能引起歧义，所以表示“不可能”常用cant，用can/could表示现在的“可能”，在口气上could比较婉转：Thats not mine. Whose can it be?It could be johns.She cant/couldnt love him.g) 用can表示“可能”，较多地用于否定句和疑问句，而could则不受此限：It cant/couldnt be true.The moon cannot always be at the full.Lightning can be dangerous.h) 在肯定陈述句中，用can表示“可能”与用may表示“可能”往往产生含义上的微妙差别：用can表示“可能”往往指逻辑上的“可能性”；而用may表示“可能”则指事实上的“可能性”：The road can be blocked.= it is possible for the road to be blocked.The road may be blocked.= it is possible that the road is blocked.i) 表示过去的“可能”，可用“may/might+不定式完成体或不定式完成进行体”，在这里用may/might，也只有口气上婉转程度的差异，而没有时间上的区别：She may/might have missed the train.He may/might have been hurt.We may/might all been indulging in an illusion.j) 也可用“can/could +不定式完成体”表示过去的“可能”：She cant/could have beem hurt.He cant/couldnt have missed the train.k) 用“might/could+不定式完成体”有时可以表示本来可能发生但没有发生，或者本来可能完成却没有完成的动作：I could have reported you.You might have killed yourself.You might have finished the work last week.2表示“许可”和“不许”A.a) 请求对方“许可（Permission）”可用can，could，may，might。may/might与can/could相比，前者较为正式；may/can与might/could相比，后者较为婉转，更有礼貌。在口语中特别常用can表示“许可”：Can/could I smoke in here?May/might I smoke in here?b) 表示给予“许可”通常用can/may，而不用could/might：Could I use your phone?Yes,of course you can.Might I trouble you for a light?You may indeed.c) 在上述诸例中，用may/can与might/could都不存在时间的差异，但在一定上下文中，便存在这种差异：Anyone may/can enroll for this course.In those days anyone might/could enroll for this course.B.a) 表示“不许”可用may not或者cannot：Can I use your car for tonight?No, you cant.May I go out for a moment?No, you may not.b) May not也可以表示一般的“不许可”，即表示根据一般规定的“不许可”，而不是说话人不许可：Borrowers may not take out of the library more than two books a time.c) 当然，表示“不许可”还可以采用其他比较婉转的说法：Could I say it in Chinese?No, I am afraid not.d) 要注意may not表示“不许可”的过去时形式并不是might not：He may not go.= I dont permit him to go.He might not go.= possibly he will not go.e) 若要表示过去的“不许可”，通常要说：He was not allowed to go.I didnt permit him to go.3表示“义务”和“必然”A.a) 所谓表示“义务”（Obligation），即表示“必须”、“应该”做某事。表示这些意义，可用should，ought to，must。用这三个情态助动词表示“义务”，其口气强弱略有差别。用should、ought to表示“应该”，带有表示“劝说”或“敦促”的含义：We should learn from the model workers.You should do what your teachers tell you to.He should do something ti help her.b) Should与ought to同义，都能表示“应该”，往往可以交替使用：You should/ought to drink less.You should/ought to tell the police.He shouldnt/oughtnt to stay up so late.c) 用should口气比较肯定一些，说话人的主观信心要强烈一些，而用ought to则在口气上不是那么肯定。“should/ought to+不定式完成体”可表示本来应该做某事却没有做或者本来不该做某事却做了：You should/ought to have asked my permission first.You shouldnt/oughtnt to have been resting at that time of day.d) 正因为should在口气上带有更多的主观信心，从而在表示强烈的劝说和敦促时，往往用should而不用ought to：You should mind your own business.e) 用must表示“敦促”或“命令”，在口气上比should更加强烈，这意味着说话人是权威的一方，对人对自都适用：You must be back by ten oclock.I really must stop smoking.f) 表示将来的“必须”，常用半助动词have to的一定形式（will/shall have to）：We must do it again.Well have to do it again.g) 表示过去的“必须”，常用have to的过去时形式had to：I must leave at six.I had to leave at six yesterday.h) Must有两个否定形式：第一个否定形式是must not/mustnt，表示“不许”、“禁止”，相应的半助动词是be to的否定形式be not to：You mustnt talk like that.You are not to talk like that.i) 上述两句的过去时形式均为：You werent to talk like that.j) Must的第二个否定形式是need not/neednt，表示“不必”：A: must you leave so soon?B: No,I neednt.k) 与neednt相当的动词形式是dont need to/dont have to/havent got to：You must do it at once.You neednt do it at once.You dont need to do it at once.You dont have to do it at once.You havent got to do it at once.l) 过去时形式通常是：You didnt need to do it at once.You didnt have to do it at once.m) 表示“必须”，must与have to意义接近，但在用法上略有区别：用must表示“必须”，侧重于说话人的主观意志；用have to表示“必须”，则侧重于客观的需要：He must say it in English.(I want him to do so)He has to say it in English.(because he doesnt know Chinese)He must move the furniture himself.(I am too busy to help him)He has to move the furniture himself.(hes got no one to help him)n) 最后，我们还要提一下：在特定语境中，用will也可表示“义务”：You will wait outside the gate.You will report to me afterwards.o) Will的这一用法，常用于第二人称主语，这实际上是一种强化的祈使句，比带有第二人称主语的祈使句口气更为强化：Parent: Brian, close the door.Brian:(no movement toward the door)Parent:Brian! You close the door.Brian:(Still no movement toward the door)Parent:Brian! You will close the door!B.a) 所谓表示“必然”（necessity）就是根据说话人的判断和推测认为“必然”会有某种情况。表示这种意义，可用should，ought to和must，其中以用must口气最为肯定。用should表示“必然”，指说话人根据一定情况作出推测或推断：She should be here in a minute.The book should appeal to all lovers of poetry.That should not be a difficult problem for Mary.Through an intensive training you should be able to pass the examination without difficulty.b) 用ought to表示“必然”也是根据一定情况作出的推测或推断：These young trees ought to provide shade in ten years.Bob has made a thorough study of this subject. He ought to be able to help you.c) 用ought to表示推断或推测与must同义，但口气较弱，从而也比较婉转：Mary Blake must be home by now.Mary Blake ought to be home by now.d) Ought to的否定形式是oughtnt to，其含义也比表示“推测”的must的否定形式cant来得婉转：You cant have any difficulty getting the tickers.You oughtnt to have any difficulty getting the tickets.e) 用must表示“必然”，也是一种推测或推断，其口气最为肯定，一般用于肯定陈述句：All men must die.Careless reading must give poor results.It must be very late because the streets are quite deserted.Your father must be expecting you home.f) 如果是推测过去的事态，则用“must+不定式完成体”：You must have left your handbag in the theatre.Her eyes are red. She must have been crying.g) 表示推测的must的否定形式是cant而不是must not：If Fred didnt leave home before five, he cant be there yet.He cant have been to your home. He doesnt know your address.4表示“预见”和“预测”A.a) 表示“预见”（prediction），即表示“单纯将来”，可用will/shall+不定式，按照18世纪以来的传统规则，shall用于第一人称主语，will用于第二、三人称主语都可表示“单纯将来”，从而认为shall和will都是“将来时”的标记。这条传统规则，尽管反映了一定时期英格兰标准英语的用法，却未能全面地确切反映will/shall这一用法在所有说英语国家的适用性。除英格兰以外的说英语国家如美国、新西兰、南非的标准英语中，shall已经完全为will所取代，这就是说，will可用于一切人称表示“将来”：I will be a different person when I live in England.We will have a great time if we go to the party.You will be hearing from me.What will you do when the war is over?Shell probably last longer than you will.The show will open on Friday.It will rain tomorrow.Will it disturb you if I keep the lamp on for a bit?b) 在非正式语体中，will更是常用于第一人称主语表示“将来”，尤其常用will/shall的缩略形式ll，从而进一步模糊了will/shall的界线：Ill book a table at Francescos.Ill come in after church and give you a hand.Well go to the party if we are invited.c) 在当代美国英语中will/shall几乎全部为will/should或者ll/d所取代。只有在法律文书中还常用I shall/we shall表示“将来”，当然并不排除shall用于第一人称主语表示“意图”和“决心”，更不排除shall用于第一人称主语表示征求对方意见：I shall never do that again.We shall catch the criminals wherever they hide themselves.Shall we go?Shall I help you?B.a) 表示“推测”（predictability），除用should，ought to和must外，还可用will/would。用will表示“推测”，其口气的肯定程度仅次于must，若用would，则口气的肯定程度又次于will：They should/ought to be home by now.They would be home by now.They will be home bu now.They must be home bu now.b) 若用would则口气不够肯定，但仍指现在时间：A:Whos that man over there?B:That will be George, no doubt. That would be George, I expect.c) 第二种是对某些习惯性事态的推测，用will指现在习惯，用would则指过去习惯，均不重读：A lion will attack a man only when hungry.Pauline will work all da without a rest.Hell stay in the laboratory for days and nights until the experiment is finished.Every day shell sit there for hours doing mothing.d) 第三种是对某些不受时限的客观过程的推测，只用will，表示现在时间，可与一般现在时的类似用法交替使用：Oil will float on water.Pigs will eat anything.5.表示“意愿”、“意图”和“决心”A.a) 表示意愿willingness，可用will，would，shall。用will表示意愿，可用于一切人称的主语，这时will不须重读并可用缩略形式llI will/ Ill lend you the money if you need it.Who will/ wholl go with me?My sister will help you with the luggage.You can help me if you will.b) 当will用于第二、三人称主语疑问句时，是询问别人是否愿意做某事，也不须重读。Will you sing at the party tomorrow evening?Will Alice accept the invitation?c) 当will用于第二人称主语请求句时，为了缓和可能含有的命令口气，可在Will you之后增添礼貌性词语。Will you please open the door for me?Will you kindly help me with the luggage?d) 表示客气的请求，用Would you？但表示接受请求时,要用will,而不用wouldWould you lend me your pen a minute?- certainly, I will.Would you write to me as soon as you arrive?- yes, I will.e) 表示不愿意用will not / wontI will not do anything solely for money.I sent Alice the invitation, but she wont accept it.Youll lend me a hand, wont you?f) 表示过去的意愿或过去不愿意做某事,可用would和would not/wouldnt,这种用法常见于间接引语中和过去时间语境中.I asked him if he would help me with my writing.When I was atcollege, I wouldnt read any books solely for pleasure.He said that he would never do anything like that.g) 用shall表示意愿一般适用于第二,三人称主语,这时,shall所表示的意愿不是句子主语的意愿,而是说话人的意愿.You shall stay with ys as long as you like. = Im willing to let you stay with us as long as.h) 用shall表示意愿,在疑问句中是征询听话人的意愿Shall you take a holiday this summer?Shall my daughter do the shopping for you?B.a) 表示意图,即打算做某事,也可用will,would,shall,用will表示意图,也是不须重读,可用缩略形式ll,并可用于一切人称主语I will write to her tomorrow.Why will you go there?Ill get some drinks. Whatll you have?We wont stay longer than two days.He wont help me unless I accept his offer.b) 如果表示过去的意图,或用在间接引语中,便可用wouldHe would see her the next day, so he didnt write to her.He said he wouldnt have any cold drinks.c) shall表示意图,常见于第二,三人称主语之后,表示说话人的意图You shall get s promotion.He shant come here.They shall not pass.d) shall表示意图,若用于第一人称主语,听起来比较古板,在现代英语的口语中通常避免使用,这时shall常为will所取代:We will /(shall) leave here this very night.I wont /(shant) go if it rains.e) shall表示意图用于疑问句中是征询别人的意见或意图shall I carry the suicase for you?Shall we have dinner?f) 在美国英语中,shall不管是表示预见,意愿或意图，都常为will所取代，几时在征询听话人意图的疑问句中，Shall I /we也常为Should I /we所取代Should I turn off the light?What should we do now?C.a) 表示决心Determination,即坚持要做某事,也可用will,would,shall,均须重读,且不能用缩略形式.用will表示决心或坚持,可用于一切人称的主语I will take the job and no one is going to stop me.I wont go back on my words.If you will eat too much pastry, you cant complain if you get fat.If you will go, you may go at once.He will go out without an overcoat although the weather is so cold.b) 如果表示过去的决心,即过去坚持做某事,便可用wouldShe would marry him.He would climb the mountain regardless of danger.The annoying thing was that she would make a muddle of almost anything.c) shll表示决心主要用于第二,三人称主语,表示说话人的强烈意志和决心You shall obey my oders.He shall leave the country at once.They shall do what I told them to.d) shall作这一用法的否定形式shall not/shant则表示说话人禁止或威胁You shant get away with it.You shall not have it, its mine.No one shall stop me.Foreign countries shall not interfere in our internal affairs.6.其他情态意义A.a) should可在某些语境中表示惋惜、忧虑、欢欣、惊讶等感情色彩。Its a pity that he should leave so soon.They were sorely distressed that their motherland should be in such great danger.They were amazed that she should have done so much in so short a time.Its unbelievable that he should be working so hard.Its marvellous that somebody should have imaginations like that.b) should在某些语境中并不表示具体的情态意义，例如在某些结构中与be-形虚拟式交替使用I insisted that he go/should go with me.It is imperative that we have/should have a strong air force.The order that all civilians be evacuated/should be evacuated was soon carried out.c) should在下列状语分句中也不带具体的情态意义They got warmly dressed for fear that they should catch cold.She took a taxi to the station so that she should not miss the train.He ran away lest he should be found bu people.d) should还可以和say,think搭配表示婉转口气I should say he is just the right man for the job.I should think your approach is correct.e) would可用于委婉的陈述，客气的请求，委婉的建议I dont think he would be so careless.It would be a shame to stop our work halfway.Would you like to stay here for the night?What would you advise me to do?Wouldnt it be better for us to start off a little earlier tomorrow morning?It wouldnt be a bad idea for us to hold two separate meetings for the two problems.f) 作为情态助动词表示胆敢，dare通常只用于否定陈述句和疑问句I dare not go there.He dare not jump from the top of the wall.How dare he say such rude things about me?g) dare作为情态助动词多用现在时形式，但它既可指现在时间，也可指过去时间The president was so hot-tempered that no one dare tell him the bad news.Tom wanted to come, but he darent.h) dare还可用作主动词。作为助动词，dare也通常用于否定句和疑问句，随后的不定式可带to，也可不带toSh