（精心整理）情态动词及例句

1、一 Can、could 1.表能力、能够(现在，过去时) Some of us can use the computer now, but we couldnt last year. 2. can 表请求和许可 1)表请求时，口语中常用could 代替 can 使语气更委婉，回答时用can - Can/Could I use your dictionary? -Yes, you can. No, you cant. 2)表示“许可”，可与may 换用 You can go home now. 3.表推测。 表惊讶、怀疑、不相信。用于否定,疑问句和感叹句。 I am sure you can&#

2、39;t play it well. How can you say that? 惊异，不相信 4.客观可能性 常用于肯定的陈述句中，表示理论上的或习惯上的可能性,”有时可能会”，不涉及具体事件。 Everybody can make mistakes. 5. could + have + done 本可以做但没做表示对过去能做而未做的事情感到惋惜，遗憾 Could not have done 不可能做 Its a pity. Your class could have got the first prize. If he studied hard recently，he couldn'

3、;t have failed the exam.二 May、might1)表示允许或征询对方许可， 允许，有“可以”之意， 一般疑问句否定回答用cant/mustnt。 在请求对方许可时，如果Might I? 就比用May I? 语气更婉转些，May I have a dance with you?-Yes，you may/can.-No, you cant/mustnt.(2)表示推测，可能性， 多用于肯，否句，“或许”、“可能”之意，如果用might表示可能性更小， may/might have done 表示对过去的事情进行可能的猜测They may be in th

4、e library now.Mary may have gone to the concert last night.3）.may表祝愿May you succeed三Must (1)must表示义务或强烈的劝告说话人主观上 “必须”、“应该”之意，其否定式 must not，缩写形式为 mustnt，表示“不应该”，“不准”、“不许可”或“禁止”之意 We must study hard and make progress every day. You mustnt touch the fire. (2)以must提出的疑问句否定回答用needn't或用don&#

5、39;t (doesn't) have to (不 必)来回答，而不用mustn't， mustn't表示的是“禁止”或“不许可”之意， -Must we finish the work tomorrow?-No, you neednt/ dont have to, but you must finish it in three days. （3）must：表推测用于肯定句（十分肯定）“一定，肯定”Betty must be in the next room. 4）. 表某人非得或偏偏做某事 Must you make so much noise?四Will

6、(1)will用于第二人称疑问句，表请求或征求意见，would 语气委婉 1)Will you lend me your book? 2) Would you like a cup of tea? (2)用于各人称，可以表示“意志”或“决心”，（would用于过去情况） I will be right here waiting for you. I would go with him if he saved my brother. (3)will可以表示一种习惯性的动作或某种倾向，有“总是”或“会要”之意， would可以表示过去的习惯动作，比used to正式，并没有“现已无此习惯”的含义

7、Every morning he will have a walk along this river. Every evening, she would sit by window, deep in thought. 4)多用于否定句中，表示“不肯、就是不 This door wont open. （5）表示公用能力“能” The room will seat 100 persons. （6）表猜测，will主要用于第二、三人称，will be(对目前情况的推测)，will have done(将来完成)。would表料想或猜想，would have done本想做而没做 Maybe by t

8、hen you will have changed your mind. 五。Shall 1. shall用于一、三人称疑问句。征求意见或请求。 Shall we dance? 2. Shall 用于二、三人称：表说话人给对方的许诺、命令”、“警告”、“强制”、“威胁”. He shall go first, whether he wants to or not. If you do well in your study, you shall get a gift. He shall be punished for what he has done. 3. Shall 与第三人称连用，在条约、

9、规定、法令等文件中表示义务或规定，意为“应该、必须” It has been announced that all people shall remain in their seats until all the papers have been collected. 六。 should 1）should 的意思是“应该”，表示给出建议或忠告询问建议。 You should learn from each other. 2）表推测，往往有一定根据“按道理应当” 有把握 We should arrive before dark. 我们按说能在天黑前到达. The roads should be

10、less crowded today. 今天路上不致於那麽拥挤了. 3.表示惊讶。意为“竟然” That he should speak to you like that is quite astonishing. 他竟然这样对你说话, 实在让人吃惊. 4)Should （not）have done表示过去没有做到本来应该做的事情，或是做了本来不应该做的事情。 You should have give him more help. 5. shouldVs ought to(should:主观原因；ought to：客观原因) As students, we should study hard.

11、 He ought to be punished because he broke the law. 七。Need 需要 dare 做情态动词时 用于否定和疑问句。 We needn't talk. We don't need to talk. dare有其过去时dared. doesnt dare (to) do I daren't go home. I doesnt dare go home. 八 . had better+动词原形 It is raining hard outside. Youd better not go out. 一、表示对过去事情的推测或估计

12、 1. must have done “想必或肯定已经做了某事” eg: The ground is rather wet, so it must have rained last night. 2. may/might have done “可能/大概已经做了某事” eg: Tom may have gone to shanghai, but I still not sure about it. 3. cant/couldnt have done “不可能已经做了某事” The ground is very dry, so it cant have rained last night 注：在

13、疑问句中 can/could 表示对过去情况的疑问性 推测，“可能已经了吗？” Someone must have broken into our bedroom, Who could have done it? 1）语气部分：（以下情态动词语气由强至弱） 肯定句：must、may、might（=could） 否定句：cant（=couldnt）、maynt、mightnt   疑问句：can、could（语气更加委婉不确定）（2）时态部分： be/do 表示对现在的推测 have done 表示对过去的推测 be doing 表示对正在进行的推测 二、表示对过去所发生事情

14、的遗憾或责备 1. should/ought to have done “过去本该做而没做 I really regretted wasting the hours when I should have studied hard, but it was too late. 2. shouldnt/oughtnt to have done “过去不该做的事却做了” Im very sorry for the words I shouldnt have said to you at that moment. 3. could/might have done “本来能够做的事却没做 He could have worked out the problem. 4. neednt have