情态动词基本用法 讲义-2025届高三英语一轮复习

常见的情态动词 Modal verbs can / could,may / might, shall / should, will / would， have to, had better, ought to, used to， must, need, dare 情态动词的语法特征 1． 情态动词 不能单独做谓语 2．情态动词没有人称，时态和数的变化，但有些情态动词，如can, may, will, dare也有一般式和过去式的变化 情态动词的基本用法 （一）can/could 1. 表能够做某事（具备某种能力）；could主要指过去能够； Two eyes can see more than one.   Could the girl read before she went to school? 2. 表许可；用于疑问句中表请求（could表示的语气更加委婉）；用于否定句中表不允许。 Can I have a look at your new pen?   You can’t wear jeans at work. 3. 表可能性或推断，多用于否定或疑问句中；若用于肯定句中表常有的行为和情形，意为“有时会/可能”； That can’t be Mary—she’s in New York. (“不可能是”) He can be stubborn sometimes. It can be cold here in winter. 4. 表疑惑或惊讶等情绪，意为“究竟能；难道会；到底是”。 What can they be doing? 他们究竟在干些什么？ Where can she have put it? 她到底把它放哪了？ （二）must 1. 用于肯定句中表说话人的意志或义务；或坚决要求某人做某事；否定mustn’t 表禁止 I must go to the bank and get some money. Cars mustn’t park in front of the entrance. 2. 在以must 开头的疑问句中，肯定回答用must; 否定回答用needn’t 或don’t have to。 —Must we hand in our exercise books now? —Yes, you must. / No, you needn’t. / No, you don’t have to.   3. 表示可能性或肯定的推断。意为“想必、准是、一定”等，只用于肯定句。 He must be ill. He looks so pale.   She’s wearing a diamond necklace. She must have a lot of money. 4. 表说话人生气或不满的情绪，意为“偏要；非得”。 — Must you interrupt now? Can’t you see I’m on the phone? —Sorry, sir, but it’s urgent. 5. 用于短语 if you must (do sth) ，表虽然不赞同但可允许，意为“如果你一定要… …的话”。 —Can I smoke here? —If you must. （三）will/ would 1. 表意愿，用于各种人称的陈述句; I will do anything for you. They won’t lend us any more money. 2. 表请求允许，用于疑问句; Will you send this letter for me, please? Would you mind leaving me alone for a few minutes? 3. 表习惯; She will listen to music, alone in her room, for hours. He would spend hours on the telephone. 4. 主语为物时，多用于否定句中，意为“不起作用”。 The door won’t open. （四）may/ might 1. 表允许，might可以指过去时间或现在时间，语气更委婉。 You may take whatever you like. May (Might) I ask for a photo of your baby? 2. 表可能（事实上）。might可以指过去时间或现在时间，但语气更加不肯定。 He may be at home, but I’m not sure.   She may/might not know about it.   3.may还可表祝愿。 May you succeed! （五）shall 1. shall用于二、三人称的陈述句，表“命令、威胁、警告、强制、允诺、决心”等。 You shall do as I say. (命令) You shall have my answer tomorrow. (允诺) Nothing shall stop us from carrying out the plan. (决心) 2. shall用于一、三人称的疑问句，表征询意见或请求允许,多与I或we连用。 What shall we do this weekend? 3. shall 常用于主语是第三人称的条约、法律法规、规章制度等文件中表“义务”或“规定”。 One of our rules is that every student shall wear school uniform while at school. （六）should 1. 表义务, 意为“应该”（某件事宜做），用于各种人称； You should be polite to your teachers.   You shouldn’t waste any time.   2. 表推测，意为“想必一定、照说应该、估计”等； The film should be very good as it is starring first-class actors.   They should be home by now.   3．（表示不确定）万一； If I should see him, I’ll tell him. If it should rain tomorrow, the sports meeting would be postponed. 4. should 可以用来表示意外，常意为“竟然；居然”。 I find it astonishing that he should be so rude to you. （七） ought to 表义务，意为“应该”（因责任、义务等该做），语气比should稍重。 You are his father. You ought to take care of him. You oughtn’t to smoke so much.   （八）双性动词need, dare 1. need 可以作实义动词或情态动词。 We need to finish the job before dark. You needn’t hurry as there’s plenty time left. 2. dare可以作实义动词或情态动词。 He dared to travel abroad when he was young. How dare you let your little child go out alone? 表推测的情态动词 1. 对现在或客观事实的肯定推测 must：肯定；准是；想必是 should：很可能；应该…, 指按常理推测 may/might：也许；大概；表示把握不大的推测 can/could：用于疑问句表怀疑 —What are you doing this Saturday? —I’m not sure, but I might/may go to the cinema. —Good morning. I’ve got an appointment with Miss Smith in the Personnel Department. —Ah, good morning. You ______ be Mrs. Peter. A. might B. must C. would D. can 2.对现在情况或客观事实的否定推测 can’t：不可能；推测的语气相当有把握 couldn’t：不可能；语气较委婉 may(might) not：可能不；也许不，推测表不大有把握 It can’t be the postman at the door. It’s only five o’clock. The younger people might not like the idea. 3. 对过去情况的推测 must have done: 过去一定做过某事 can’t have done/ couldn’t have done: 过去不可能做某事 can/could have done: 过去可能做过某事 may/might(not) have done: 过去可能（没）做过某事 Since nobody gave him any help, he ____ have done the research on his own. A. can B. must C. would D. need Why are your eyes so red? You ______ have slept well last night. A. can’t B. mustn’t C. needn’t D. won’t 考点三：情态动词+ have done 的其他用法 should/ought to have done 表过去本该做却没有做 shouldn’t/ ought not to have done 表过去本不该做却做了 could have done 表本可以/本可能做某事却没做 might have done 表本可能但实际没有发生的事 needn’t have done 表本来不需要做却做了 1.may/might + have done 表示对不太把握的过去情况的可能性推测，表示“可能/大概已经做了某事”。 Tom may have gone to Shanghai, but I’m still not sure about it. 汤姆可能已经去了上海，但是我还不能肯定。 Jack didn’t come on time. He may/might have missed the bus.2 杰克没有准时来，他可能是错过了公交车。 2. must + have done 表示对过去发生的事情或行为比较有把握的推测、肯定的推断，译为“一定做了某事；准是做了某事”等。否定意义用can’t/couldn’t have done表示。 Since nobody gave him any help, he must have done the research on his own. 因为没有人给他提供帮助，他一定是自己完成了研究。 The ground is rather wet, so it must have rained last night, didn’t it? 地面很湿，所以昨晚一定下雨了，对不对？ 3.should/ought to + have done 表示过去本应该做却没有做的情况，表示说话人后悔、遗憾或责备的语气。 I really regret wasting the hours when I should have studied hard. 我真的很后悔该努力学习的时候浪费了太多时间。 —Sorry, Mum! I failed the job interview again. —Oh, it’s too bad. You should have made preparations. Instead you spent all your time playing computer games. 4.shouldn’t/oughtn’t to + have done 与前面的相反，shouldn’t /oughtn’t to + have done表示本不该做某事却已经做了，也表示说话人后悔或责备的语气。 You shouldn’t have watched TV last night. 你们昨晚本不应该看电视的。 I shouldn’t have watched that movie — it’ll give me horrible dreams. 我不该看那部电影的，它会让我晚上做噩梦的。 5.needn’t + have done 表示过去做了不必要的事，可译为“本可不必”等。 You needn’t have visited my uncle, as he has been all right for long. 其实你不必去探望我叔叔的，因为他已经痊愈了好长一段时间了。 I needn’t have worried before I came to the new school, for my classmates here are friendly to me. 在去新学校之前我本不必担心的，因为我的同学对我很友好。 6.could + have done “本来可以/能够做却没做”，表示懊恼和惋惜。 You could have done better，but you were too careless. 你本来能够做得更好，但你太粗心了。 He could have escaped, but he chose to stand and fight. 他本可以逃跑的，但是他选择留下来战斗 7. can’t/couldn’t + have done 是must have done 的否定式，表示“一定没有做过某事, 不可能做过某事 ”。 Without your guidance, I couldn’t have spent such a happy time. 没有你的指导，我不可能度过如此愉快的时间。 Mr Smith can’t have gone to Beijing, for I saw him in the library just now. 史密斯先生不可能去北京了, 我刚才还在图书馆见过他。 —Why are your eyes so red? You can’t/couldn’t have slept well last night. —Yeah, I stayed up late writing a report. 为什么你的眼睛这么红？你昨晚一定没有睡好。 是的，我熬夜写了一篇报告。 1. 他意识到一定有什么人进过他的房间。 He was aware that someone ___________________ his room. 2. 你这么晚的时候本不应该一个人来这里的。 You ____________________________ here alone at such a late hour. 3. 她本不必亲自来——写封信来就足够了。 She ________________ in person—a letter would have been enough. 4. 我找不到我的钥匙了。我可能昨天把它们落在学校了。 I can’t find my keys. I __________________ them at school yesterday. 1. must have entered 2. shouldn’t/oughtn’t to 3. have come needn’t 4. have come may/might have left When my English teacher suggested that I read Charles Dickens’s A Christmas Carol, I thought, “I (1)____________ (can’t/shouldn’t) read this! It (2)_________ (has to/must) be very boring.” Surprisingly, it turned out the exact opposite. I (3) ________(could/might) not stop turning the pages! The book’s main character is Scrooge, a rich but mean old man. He hates all kinds of celebrations. On Christmas eve, he is transported to different points in his life by three spirits. In the end, he reflects on these moments and realizes his mistakes. Then he decides that he (4)___________(might/must) change himself. On Christmas morning, he sends a large turkey to a poor man for Christmas dinner. He also tries to make his family and friends happy by spending time with them. There is something that (5)_______(can/must) be learnt from A Christmas Carol: we (6)__________(should/may) treat others with kindness, generosity and love. I think everyone (7)______________(would/ought to) read this book. 1. can’t 2. must 3.could 4.must 5.can 6.should 7.ought to 1.— What’s the weather like in your hometown? Is it cold in winter? — Yes, it (be) as cold as -30℃ in winter. 2. —I want to invite Tom to see a film tonight. Has he arrived yet? —Yes, he just arrived. But after four hours’ ride, he _____ (be) tired now and he (prefer) to stay in tonight. 3. —Is Betty still playing the piano? —Yes. I asked her to stop and take a rest, but she (not listen). 4.—What does the rule say about using the reading room? — No one (talk) loudly. 5.— Your car looks great. It (cost) you a lot of money. — Yes, it’s quite expensive. 6.— How long can I keep the book? — The books that students borrow (return) to the library within two weeks. 1.can be 2.must/may/might be may/might prefer 3.wouldn’t listen 4.shall/should talk 5.must have cost 6.must/shall be returned 学科网（北京）股份有限公司 $$