情态动词大盘点––––小议其语法功能及应用 情态动词如何使用，是中考中必须面临的问题，下面主要从语法功能的角度对其进行总结：一. 情态动词常规用法归纳 1. 表示能力：can / could常表示总的能力，而be able to则多表示某一特定的能力，表示将来的能力常用will be able to. 情景例句： He could swim in the river when he was only seven. She is able to talk with others in several languages. If you work harder, you will be able to catch up with the top students in your class. 2. 表示许可：may用于正式场合，can用于非正式场合，could用于客气的询问，might极少用must not表示“不许，一定不要”，语气很强 情景例句： Put that cigarette out. You must not smoke at the gas station. Could I have a glass of water? Can they take these books out of the reading room? 3. 表示必须：用must或have to（口语中常用have got to）表示“必须”，其中needn’t与must相反，not have to与have to相反，表示“不必”。
而过去不必要则用didn’t have to表示 情景例句： You didn’t have to hurry because you had plenty of time. 4. 表示建议和责任：用should和ought to表示责任和劝告，后者的语气更强一些口语中也常用had better表示“最好（做或不做某事）” 情景例句： You should / ought to do as you required. 5. 表示建议 （1）用shall I / we....征求对方意见 （2）may / might as well用于推荐更佳方案，意为“倒不如……、还是……的好” （3）may / might just as well表示建议另一种方案，含义为“……不也一样吗？” 6. 表示意愿： （1）You/ He/ She/ They shall表示说话人的强烈意愿，即“一定要”他人做某事 （2）Will/ Would也用于表示意愿 （3）Will/ Would you表示客气的建议或征询意见 7. dare say的用法：dare say常写作daresay，表示可能、或许；也可以表示当然、很可能，相当于probably / expect / suppose等含义。
情景例句： I dare say they will not come. It’s not her fault, I daresay.二. 情态动词表推测 1. 表示对现在或将来情况的推测： may表示的可能性比might大，而口语中也可用can/ could表示可能must表示非常肯定口气might/ may/ must＋不定式”表示对现在发生的事情的推测，“might/ may/ must＋不定式的完成式”表示对过去发生的事情的推测，它们的否定形式一律都用can’t （1）询问“可能”用can，回答“不可能”用can’t （2）表示过去的可能性可用“may/ might＋不定式的完成式”，推测过去某动作“也许”发生了，may比might的可能性大些 情景例句： There is no light in his room. He may/ might have gone out. I can’t find my sunglasses, I may / might have left them at the restaurant yesterday. （3）must表示“一定”，即最有可能。
但仍然是一种主观的推测，而不是客观的事实其否定式用can’t 情景例句： The phone is ringing but there is no answer. She can’t be at home. 补给站： a. “might + have + -ed分词”还可以用来表示对本来可能发生而未发生的动作的感叹或遗憾，或者说轻微的责备 b. “could + have + -ed分词”表示推测过去某动作“很可能发生了” c. “must + have + -ed分词”表示推测过去某动作“肯定发生了”它的否定形式can’t / couldn’t have done表示过去某动作肯定没有发生过 综上所述，表示推测过去动作发生的可能性，就肯定形式而言，must, could, may, might的可能性依次递减而且can的肯定形式一般不用于这种情况，而can’t则可用来表示对过去动作的否定推测 （4）“should / ought to + have + -ed分词”表示过去某动作应该发生而实际未发生，有“本来应该”的意思 情景例句： ––– I didn’t work very hard. So I failed in the examination. ––– It’s a pity. You should have worked hard at your lessons. 其否定式表示不应该发生的情况，却又发生了。
情景例句： You shouldn’t have told them about the meeting. ( But you actually did it. ) （5）“needn’t + have + -ed分词”表示“本来不必”的含义 情景例句： –––– We went to the meeting but it had been cancelled. –––– Oh, so you needn’t have gone.（你本来不必去的） 但是，这个结构与didn’t need to的意义不同didn’t need to指“不必”，强调在过去时间里没有必要（因而通常没有）做某事 情景例句： They told us the meeting was cancelled, so we didn’t need to go. （6）“Would + have + ed-分词”用于虚拟语气表示与过去事实相反的主句中 情景例句： If I hadn’t missed the bus, I would have taken part in their evening party on time. 2. “情态动词＋不定式进行式”表示对正在进行的情况的推测： （1）“情态动词＋不定式进行式”表示推测或评论某动作现在是否正在进行。
（2）“情态动词＋不定式完成进行式”表示推测或评论过去某动作是否在进行或一直在进行［巩固练习］ 1. My daughter _____ my letter, otherwise she would have replied before now. A. has received B. ought to have received C. couldn’t have received D. should have received 2. From tears in her eyes we can deduce that something sad ______ . A. must have occurred B. would have occurred C. might be occurring D. should occur 3. The millions of calculations involved, had they been done by hand, _____ all practical value by the time they were finished. A. could lose B. would have lost C. might lose D. ought to have lost 4. My pain _____ apparent the moment I walked into the room, for the first man I met asked sympathetically, “Are you feeling all right?” A. must be B. had been C. must have been D. had to be 5. You _____ all these parcels yourself. The shop would have delivered them if you had asked a shop assistant. A. didn’t need to carry B. needn’t have to carry C. needn’t carry D. didn’t need carry 6. The streets are all wet. It ______ during the night. A. must be raining B. must have been rained C. must be rained D. must have rained 7. I should like ________ the results earlier. A. to tell B. having told C. to have told D. to have been told 8. He can’t plead ignorance as his excuse; he ______ what happened in his own department. A. would know B. should have known C. had known D. has known 9. Since she is angry, we ______ her alone. A. had better leaving B. must leave C. can leave D. might as well leave 10. Come what _____, we’re not going to make any concession to his unreasonable demands. A. must B. should C. can D.。