1、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 towillwouldshallshouldneedneededdaredaredC. 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 notcantHe cant ski.他不会滑雪。could notcouldntI couldnt
2、speak English fluently then.那时候我不能流利地讲英语。must notmustntYou mustnt think only of yourselves.你们不能只想自己。should notshouldntWe shouldnt be so careless.我们不应当这样粗心大意。ought tooughtntThere oughtnt to be much noise in a library.图书馆里不该喧闹。will notwontI wont do so.我不愿这样做。would notwouldntHe wouldnt go to bed before
3、 he finished his homework.他在完成作业以前不愿睡觉。shall notshantYou shant leave your post.你不得离开岗位。need notneedntYou neednt go there alone.你不必单独去那里。dare notdarentShe 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.
4、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.因为累了，他不能游过河。表示表示可能性1. If we dont have a guide, we can lose our way in the forest假如没有向导，我们有可能在森林里迷路。2. We have just bought 50kg of rice. We cant be in short of food. 我们刚买了50公斤大米，我们不可能缺粮。表示请求，命令，惊讶等1. Can you lend me your
5、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用于疑问句中表示请求，语气比较委婉，但肯定回答时要用can，而不用could.1. -Could you lend me your book? 把你的书借给我好吗？-Certainly, I can. 当然可以。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
6、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：1. I was able to (managed to) finish my homework in an hour.我终于在1小时内做完家庭作业了。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
7、，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当might代替may时,在语气上更委婉1. You may use my camera. 你可以用我的摄像机。2. May /Might I come in? 我可以进来吗？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
8、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 as well stay where we are.2. You may as well consult a dictionary.
9、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1. The lady cant be only 30. She must be 50. 那位女士不可只有30岁。她肯定50岁了。2. The old man must be our hi
10、story teacher. 那位老夫子肯定是我们的历史老师。后面加动词不定式的完成式表示对过去事物的推测Mike speaks Chinese very well. He must have studied Chinese before. 迈克的汉语很棒,他以前肯定学过汉语的后面加动词不定式的进行式表示对现在进行事物的推测She must be waiting for us.她一定在等着我们。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 tr
11、ue?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:用法例句用干各种人称，表示意愿、意志或决心1. I will do anything my country asks me t
12、o 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. 小红说她愿意帮助我学习数学。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. Fi
13、sh will die without water. 没有水鱼就会死。2. They will have a party every Saturday evening.他们总会在周六晚上举行晚会。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
14、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.我宁可呆在家里也不愿意去看电影。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
15、 dont any more. 我过去烟瘾很重，但现在不抽了。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. Ben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
16、 again before long.不久你就会见到她。（允诺）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。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？Shall I close the door? 要不要我把门关上？Lets go to the cinema, shall we?我们去看电影好吗？Should（表示义务责任）应当，应该Should have done含责备之意1. You shou
17、ldnt 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, 1. If he should fail to come, ask Jack to work in his place. 万一他不来，就叫杰克代替他工作。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
18、、推测、推论）可能, 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
19、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 do
20、ctor 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。后面接肯定的动词不定式的完成式表示过去该做而未做的事，如接否定的动词不定式的完成式，则表示一件不该做的事情发生
21、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) 需要和你一起到超市去吗？-No, you neednt. Ill manage all by myself. 不必了，我自己能设法去的。2. Tom doesnt need to com
22、e 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 来了，但实际不必来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） 这女孩晚上不敢出门。2. Dare you climb such a steep cliff? 你敢攀
23、登如此陡峭的山崖吗？3. He doesnt dare to cross the river.（实义动词） 他不敢过河。情态动词have done用法例句表推测时：may/might have done（语气不肯定）过去可能cant/couldnt have done（语气肯定）过去不可能must have done（语气肯定）过去一定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
24、 during the night.3. The streets are all wet, it must have rained during the night.表责备时：may/might have done过去本可能做而未做can/could have done过去本能做而未做should have done过去本该做而未做ought to have done过去本应该做而未做neednt have done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 li
25、sten 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
26、 for him. A whole night was wasted.语法专练一、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. H
27、e 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 _ fin
28、ish 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
29、. 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. should have drawn a mapC. ought to draw a mapD. must have drawn a map11. She is late. What _ have happened t
30、o her?A. shouldB. mustC. canD. would12. We were waiting for you this time yesterday.Sorry, I _ you to tell you that I couldnt come.A. must have calledB. would have been callingC. could have been callingD. should have called13. You _ swim even faster than he if you practice more.A. mustB. canC. ought
31、 toD. have to14. I wonder why its so dark. There _ be a heavy rain coming.A. shallB.mustC. shouldD. will15. They _ not to make so much noise in the classroom.A. needB. dareC. canD. ought16. You _ return the bike right now. You can keep it until he wants to use it.A. mustntB. may notC. cantD. neednt1
32、7. Its fine and sunny outside. _ we go out for a walk?A. MustB. WillC. WouldD. Shall18. The meeting has already begun. You _ 10 minutes ago.A. should comeB. ought to comeC. must have comeD. ought to have come19. Little Franz wasted a lot of time playing when he _.A. should studyB. must studyC. shoul
33、d have studiedD. must have studied20. If your group leader is not right, you _him.A. mustnt obeyB. dont have to obeyC. wouldnt have obeyedD. cant have obeyedKey:1-5 CACBD 6-10 BDDAB 11-15 CDBBD 16-20DDDCB二、动词填空（用适当的情态动词填空）1. A: There were already five people in the car but they managed to take me as
34、 well. B: It _ have been a comfortable journey.2. A: Jack, you _ play with fire. You _ hurt yourself. B: OK, mum.3. A: Will you stay for dinner? B: Sorry, I _. My mother is waiting for me at home.4. A: My new pencil-box has disappeared. B: Who _ have taken it?5. A: She looks very sad. You _ have tol
35、d her the bad news. B: But I didnt mean to hurt her.6. A: _ you succeed! B: Thanks a lot.7. A: A computer _ think for itself. B: You are right. It _ be told what to do.8. A: Shall I tell Mary about it? B: No, you _. I have told her already.9. A: You _ call him if you want to. B: I _! He is sure to c
36、all me.10.A: Im told Tom had another car accident this morning. B: I cant believe it. He _ have been so careless.Key: 1. couldnt 2. mustnt/shouldnt, may/might/could 3. cant 4. might/could 5. shouldnt 6. May 7. cant, must 8. neednt 9. can, neednt 10. couldnt三、句子翻译1. Michael should have come to school
37、 a little earlier in the morning. 2. Barbara may/might have been ill last week. 3. They should be here by now. 4. He ought to know her telephone number. 5. Shall I close the door? 6. 这个女孩法语讲得很流利，她肯定在法国待过多年。7. 你不应当整夜玩电脑游戏。8. 昨天是星期天，我们不必上学，我们整天待在家里。9. 你没有必要说那种话，要不要我提及你昨天买的那条令人恶心的领带？10. - 需要和你一起到超市去吗？
38、不必了，我自己能设法去的。Key: 1. 迈克尔早上应该早一点到校。2. Barbara上星期可能生病了。3. 他们现在应该到了。4. 他应当知道她的电话号码。5. 要不要我把门关上？6. The girl speaks French quite fluently. She must have been in France for years.7. You ought not to have played e-games all night through.8. It was Sunday yesterday. We didnt need to go to school. We stayed
39、at home whole day.9. You neednt have said that. Shall I mention the terrible tie you bought yesterday?10. -Need I go with you to the market? -No, you neednt. Ill manage all by myself. 四、句子改错 (下列各句分别有一处错误，指出并改正)1. When I read the story, I wouldnt help thinking of my days in the countryside.2. They da
40、re not to express their views boldly.3. You cant write to him, he will come back tomorrow.4. You mustnt work tomorrow if you dont want to.5. He suggested that we would go together.6. Whatever the difficulties, we must realize the four modernizations.7. She mustnt be hungry; she has only just finishe
41、d supper.8. He is honest. He mustnt have done such a thing.9. You cant walk on the grass.10. Must it rain tomorrow，the meeting would be postponed.Key: 1.wouldnt 改为couldnt 2. 去掉to 3.cant 改为neednt 4. mustnt 改为neednt 5. would 改为should 6. must 改为will 7. mustnt 改为cant 8. mustnt 改为cant 9. cant 改为mustnt 10. Must改为 Should