情态动词方春俞.doc

M4U2Grammar-情态动词A. 特征特征情态动词有一定词义，但不完全，不能单独作谓语，须和不带to的动词不定式（ought等除外）一起构成合成谓语；情态动词没有人称和数的变化；情态动词表示可能，能力，允诺，命令，愿望，敢于等情态。B. 基本形式原形过去式cancouldmaymightmustmust (or: had to)ought toought towillwouldshallshouldneedneeddaredaredC. 情态动词和否定词not连用时的简略形式情态动词not简略形式例句can notcant不能 不可能He cant ski. 他不会滑雪。He cant be in the classroom. He is in the library.could notcouldnt不能;不可能I couldnt speak English fluently then.may not可能不He may not be at home, Im not sure.must notmustnt 禁止，不允许You mustnt think only of yourselves.你们不能只想自己。should notshouldnt不该，不应当We shouldnt be so careless. 我们不应当这样粗心大意。ought tooughtnt不该，不应当，理该不There oughtnt to be much noise in a library.图书馆里不该喧闹。will notwont 不愿意I wont do so. 我不愿这样做。would notwouldnt不愿意He wouldnt go to bed before he finished his homework.他在完成作业以前不愿睡觉。shall notshant 不得，不该You shant leave your post. 你不得离开岗位。need notneednt 不必；没必要You neednt go there alone.你不必单独去那里。dare notdarent 不敢She darent swim in a river. 她不敢在江河游泳。D. 情态动词的用法can /could 的用法：用法例句表示能力1. My daughter can speak three languages quite well: Chinese France and English. 我女儿能流利地讲三种语言：中文、法文和英文。2. Because he was tired, he couldnt swim across the river. 表示表示可能性1)肯定句中表“有时会，可能会”； 2)否定句中表“不可能”3) 疑问句中，只能用can, could 表可能性1. If we dont have a guide, we can lose our way in the forest2. We have just bought 50kg of rice. We cant be in short of food. 3. Doing exercise alone in the gym can be very dangerous.4. Can he come back tonight?5. Could the boy have been lost in the big city?表示请求，命令，惊讶等1. Can you lend me your bike? 你能将自行车借给我吗？2. You can bring the calculator tomorrow. 明天你们要带计算器来。3. How can he be so rude? 他怎能这样无礼?Could用于疑问句中表请求，语气较委婉，但肯定回答时用can，而不用could。1. Could you lend me your book? -Certainly, I can.2. Could you let me have your pass? 看看你的通行证好吗？说明can 和be able to都可以表示能力，但它们的过去式在意义上有点差别，could偏重于表示某人过去有某种能力，但并不明确表示某人干了某事，而was/were able to 则表示过去某人有能力干某事，实际上干了某事。另外，be able to 有更多的时态形式。如：I was able to (managed to) finish my homework in an hour.2. Chuck has been able to realize that friendship is about feelings and we must give as much as we take. 查克能够明白这样的道理：友谊就是感情，我们既要得到关爱，又须给与别人同样多的关爱。may/might的用法：用法例句表示允许和请求might在语气上更委婉。注意疑问句的回答。1. You may use my camera. 你可以用我的摄像机。2. May /Might I come in? Sure. 我可以进来吗？当然可以。3. - May / Might I watch TV after finishing my homework?- Yes, you may. / No, you mustnt. / No, you may not. / No, youd better not. 表示可能性1. She may not be free today. 今天她可能没有空。2. He might come to see you this evening. 今晚他可能来看你。用在由so that或in order that引导目的状语从句中1. She saved her money in order that she might buy a watch.为了买块手表，她节省钱。2. I am saving my money so that I may go to Australia next winter.我正在攒钱，以便明年冬天到澳大利亚去。表示祝愿1. May you have a good time / 2. May you succeed.表示让步Try as he may, he cannot find her.表示建议（和as well连用）1. We may / might as well stay where we are.2. You may / might as well consult a dictionary.Must 的用法：用法例句表示必须，必要，mustnt (must not) 表示禁止，不准1. You must come to school early enough for the morning class. 你必须早晨到校上早读课。2. You mustnt talk to your father like that. 你不能那样对你父亲讲话。表示主语的肯定推测, “一定”“准是”，比may肯定得多;后面加动词不定式的完成式表示对过去事物的推测后面加动词不定式的进行式表示对现在进行事物的推测1. The lady cant be only 30. She must be 50. 2. The old man must be our history teacher. 3. Mike speaks Chinese very well. He must have studied Chinese before. 4. She must be waiting for us, isnt she? 5. You must have seen the film, havent you?6. You must have seen the film last week, didnt you?7. His parents may have beaten him, havent they?8. His parents cant have beaten him yesterday, did they?9. He must have finished reading the novel by yesterday, hadnt he?10. Your mother must have been told the truth just now, wasnt she?用于if从句中，表“一定要，非得要”Ill tell you the truth, if you must. 表示推测的否定和疑问结构不能用must须用can1. The door is locked; she cannot be at home. 门锁了，她一定不在家。2. Can the news be true? 这消息可能是真的吗？说明must 和have to 都可以表示必须，但must 着重说话人的主观看法，而have to强调客观需要。 另外，have to 有多种时态形式。如：1. We must learn at least a foreign language well. 我们必须学好至少一门外语。2. Mother was ill, so I had to look after her at home. 母亲病了，我得在家照顾她。will/would的用法:用法例句用于各种人称，表示意愿、意志或决心; 可用于if条件句中1. I will do anything my country asks me to do.我决心做祖国需要我做的任何事。2. Xiao Hong said that she would help me with my maths. 3. If you will listen to me, Ill give you some advice on how to learn English 用于第二人称的疑问句，表示征求对方的意见或向对方的请求。Would 比will更委婉客气些1. Will you give this note to Tom as soon as he comes back? 汤姆一回来，你把便条给他，好吗？2. Would you mind explaining it again?请你能再解释一遍好吗？will表示现在的某种倾向或习惯。 Would 表示过去习惯发生的动作1. Fish will die without water. 没有水鱼就会死。2. They will have a party every Saturday evening.3. He would go for a walk every evening when he stayed at the hotel. 当他位住在旅馆的那段时间，他有每天傍晚散步的习惯。would like“愿意，要”1. I would like to hear your opinions. 我愿意听听你的意见。2. Would you like to have a chat with me? 你愿不愿意和我一起聊天？would rather “宁愿，较喜欢”1. I would rather stay at home than go to the cinema.2. He would rather have tea. 他喜欢茶。3. I would rather not go to the concert. 我宁愿不去参加音乐会。说明would 和used to 都表示过去的习惯，但used to 表示这种习惯现在已停止，used to 后面可用状态动词或动作动词，而would后只能用动作动词。 1. I used to smoke heavily, but I dont any more.2. He would go to see his grandfather on Sunday when he was in middle school. 他中学时星期天常去看望祖父。3. Ben used to be a heavy smoke. 本曾经是一杆老烟枪。shall/should 的用法：用法例句Shall (表示说话者的意图、许诺、警告、命令、决心等，用于陈述句第二、三人称中) 必须，应1. You shall not leave your post. 你不得离开岗位。（命令）2. You shall see her again before long. 不久你就会见到她。（允诺）3. You shall go to the front at once(命令)4. Dont worryYou shall get the answer this very afternoon（允诺） 5. He shall be sorry one dayI tell you(警告)6. Nothing shall stop us from fighting against pollution(决心)shall (表示强烈意志和不可避免性，用于陈述句第一、第三人称) 一定1. We shall have to be ready.我们一定得准备好。2. He is determined that nothing shall stop him. 他已下定决心什么也阻挡不了他。shall (在条约、规章、法令等文件中表示义务或规定，一般用于第三人称) 应，必须The new regulation shall take effect on June 1st.新章程自6月1日起施行。The shares of the company shall be divided among the family members.这家公司的股份应在该家族成员间分配。shall (在问句中表示征求对方意见，主要用于第一、第三人称) 好吗？要不要？1. Shall I close the door? 要不要我把门关上？2. Lets go to the cinema, shall we? 我们去看电影好吗？3. Shall I /we / he / she / they / Tom / Rose / my brother go to the concert with you this evening？ (征求意见)should（表示义务责任）应当，应该should have done含责备之意1. You shouldnt be so careless.你不应该这样粗心大意。2. He should have told me the news earlier.他本来应该早些告诉我这消息。should（表示语气较强的假设）万一, 竟然1. If he should fail to come, ask Jack to work in his place. 2. Should it rain tomorrow (或If it should rain tomorrow), the meeting would be postponed. 万一明天下雨，会议就延期。should（表示可能性、推测、推论）可能, 理该1. They should have arrived in Beijing by this time. 他们这是该已到北京了。2. The report is written after careful investigation, so it should be reliable. 这份报告是经过周密调查写成的，所以该是可靠的。should（表示委婉、谦逊）可, 倒1. I should like to have a talk with you. 我想跟你谈一谈。2. You are mistaken, I should say. 据我看，你可搞错了。should（用于表示必要、适当、惊奇、遗憾等的从句中）应该；竟然会1. It is proper that no hasty decision should be made. 不应当做出匆促的决定。2. It is astonishing that we should find violence here. 我们这儿竟然有暴力行为，真令人震惊。should (用于表示建议、命令、决定等的从句中)应该, 必须1. He suggested that we should make better use of the school library.他建议我们应该更好地使用学校图书馆。2. The young doctor proposed that he should try the experiment on himself. 青年医生建议在他自己身上做实验。ought to 的用法用法例句should/ ought to 都表示义务、责任。ought to 的语气要更强一些1. You ought to be attentive at class. 你在课上应当思想集中。2. He oughtnt to be so careless in his work. 他在工作中不应该如比粗心大意。ought to have done表示过去该做而未做的事，ought not to have done则表示一件不该做的事情发生了1. I ought to have washed my clothes last night.我昨晚就应当洗衣服了。2. You oughtnt to have wasted so much time.你不该浪费这么多时间。need/dare 的用法：用法例句need作情态动词常用于否定句或疑问句中，做实义动词不受限制1. -Need I go with you to the market? ( 情态动词) -No, you neednt. Ill manage all by myself. / Yes, you must. 2. Tom doesnt need to come to the meeting tomorrow. (实义动词)汤姆不必明天来参加会议。 need后面跟动词不定式的完成式，用在否定句中，表示做了本来不必做的动作Your elder brother need not have come last night. 你哥哥昨天晚上本来无需来的。need not have come指来了，但实际不必来did not need to come则表示不必来，实际上没有来dare作情态动词常用于否定句或疑问句中，做实义动词不受限制1. The girl dare not go out at night. （情态动词） 2. Dare you climb such a steep cliff? 3. He doesnt dare to cross the river.（实义动词）4. How dare you say Im unfair?情态动词have done用法例句表推测时：(表陈述)may/might have done（语气不肯定）过去可能做了某事cant/couldnt have done sth.（语气肯定）过去不可能做了某事must have done sth.（语气肯定）过去一定是发生某事了should have done sth. 应该已做完某事；竟然做了某事（表惊讶）1. -I didnt see Mary at the meeting yesterday. -She might have been ill, I guess.2. The streets are all dry. It couldnt have rained during the night.3. The streets are all wet; it must have rained during the night.4I hardly imagine such a gentleman should have been so rude to the old lady.5. They should have arrived in Beijing by this time.表责备时：（表虚拟）might have done sth.过去本可能做而未做could have done sth.过去本能做而未做should have done sth.过去本该做而未做ought to have done sth.过去本应该做而未做neednt have done sth.过去本不必做却做了1. He might have given you more help, even though he was very busy.2. -Did you listen to the speech? -No, we could have attended it. But we had a lot of traffic on our way.3. The plan is dead. Maybe I should have given more water.4. Your brothers failed in English again. You ought to have given him more help.5. -Mr. Smith didnt come last night, did he? -No. We neednt have waited for him. A whole night was wasted.表意愿时：（表虚拟）would have done sth.想做而未做，本可以做而未做would like to have done sth. 想做而未做would rather have done sth.宁愿做某事而未做1. If you had come five minutes earlier, you would have seen the famous star. 2. I would like to have gone to your help, but I was too busy.3. The film was a bore. I would rather have stayed at home.语法练习一、单项选择1. You didnt go to the party yesterday, or I _ you. A. would seeB. could seeC. might have seenD. might see2. He _ at the meeting this morning. He was in hospital then.A. cant have spokenB. mustnt have spokenC. shouldnt have spokenD. neednt have spoken3. He must be in the classroom, _ he?A. cantB. mustnt heC. isntD. neednt4. You _ have brought your camera. They all had theirs with them.A. couldntB. neednt C. wouldntD. mustnt5. My little son _ out alone at night. A. dares not goB. dares not to goC. dare not to goD. doesnt dare to go6. At last he _ finish the work ahead of time.A. couldB. was able toC. could be able toD. can be able to7. There must be some soldiers hidden in the forest. _ any behind the church?A. Must there beB. Should there beC. May there beD. Can there be8. If anybody _ to see me, say that I shall be back soon.A. would be comeB. comesC. cameD. should come9. Could I have a word with you?- Yes, _.A. you canB. you couldC. you mustD. you should10. I told him how to get here, but perhaps I _ for him.A. had to draw a mapB. sho