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1、1情情态态动动词词和和虚虚拟拟语语气气讲讲义义考点一：情态动词的基本用法考点一：情态动词的基本用法 1. can, could, may, might 的用法的用法 1) can 表示能力，意为“能够；懂得；会” 。could 表示过去的能力；其将来时用 be able to 代替。 This machine can perform two million calculations per second. I can speak five languages. 注意：be able to 表示“能够做某事而且做成功了” 。 He was able to do that without any
2、help. 他不需要任何帮助就完成了这项工作。 2) can, could, may, might 表示请求 (permission)、允许或许可。常用在口语中，其中的 could 语气较 委婉，不用于肯定句，答语要用 can；could 都还表示委婉客气的提出问题或陈述看法；might 表示 委婉的请求。 The goalkeeper cant handle the ball outside the penalty area (禁区). Could I use your bike? 我可以用你的自行车吗？ Yes, you can./Im afraid not. 可以，用吧。 No, you
3、 cant/mustnt. 不行。 May/Can take the book out? 我可以把这本书带走吗？ Yes, you may/can. 可以。No, you may not. 不可以。 （委婉） No, you cant/mustnt. 不行。 （强烈） 3) can 与表示感官和思维的动词连用。 You can really taste the garlic in that soup. You can imagine how annoyed she was! 2. must 的用法。的用法。 must 既表示义务或强制，意为“必须；一定要” ；还可表示肯定性，意为“必然会；肯定
4、 会” ；作“偏要；硬要”解时，用于第二人称时，表示不耐烦或令人不愉快的事情；用于其他人称， 表示主语“固执”的意味。 If you cant finish the book by then, you must come and renew it. Im afraid I must go now; I promised to be home at ten. Dont bet on the horse race; you must lose in the long run. If you must know, Im going to help him look for an apartment.
5、 Jane was never a pleasant young girl. After you gave her your advice, she must go and do the opposite. must 的否定形式有两种：当 must 表示“强制或义务”时，其否定意义为“一定不要” ，表示不许 或禁止，将 must do 改为 must not do；当 must 表示“必须”时，其否定含义为“不必” ，将 must do 改为 need not do 或 dont have to。 We mustnt waste our time. 我们不应该浪费时间。 You need no
6、t/dont have to get up at six tomorrow morning. 明天早上你不必六点起床。 注意：1) must 可以用作名词，意为“必须有的东西（做的事） 。 Dont miss latest play; its a must. /Warm clothes are a must in the mountains. 2) 词组 be sure to, be certain to, be bound to, be due to 都有“一定；肯定；务必”等意义。2He informed us that the boat was due to leave at 4. /T
7、he plan is bound to succeed. 3. shall 的用法。的用法。 在疑问句中，用于第一、三人称，表示征求对方的意见；用于第二、三人称时表允诺，警告，命 令，威胁等；在法律、条约、规章等文件中，表示义务、规定。 What shall I wear on the journey? /Shall he start at once or wait for a while?She shall get her share. /You shall fail if you dont work harder. House owners shall keep their gardens
8、 in a neat and ordinary state. Each citizen shall carry his identification card when traveling. 4. should 和和 ought to 的用法。的用法。 should 表示“劝告、建议、命令” ，其同义词是 ought to (否定式 ought not to do)；should 还可表示 义务，意为“应该” ；也可表示惊讶，忧虑，惋惜等情绪，意为“竟会；竟然” ，常用在 Im surprised; It worries me; Its a pity; You cant imagine 等结构
9、中。 You should/ought to go to class right away. He should do some work, but he doesnt want to. I find it quite astonishing that he should be so rude to you./You cant imagine that a well-behaved gentleman should be rude to a lady. 5. will 和和 would 的用法。的用法。 will 可以表示意志，决心或愿望；也可表示经常性、习惯性、倾向性，表示某事总是发生或一般
10、如 此；也可表请求；还可表示“老是” ，用于描述某人奇异或令人烦的习性，用在第三人称。would 也可表示愿望，还表示过去的习惯行为，用于第二人称作主语的疑问句中，表示对对方的请求。 Surely we will support all the people in the world in their struggle for peace. I will come up and help you clean the room in a moment. Oil will float on water./ Accidents will happen. He will sit there hour
11、after hour looking at the traffic go by./Trish will keep asking silly questions. During the vacation he would visit me every week. 注意：wont 或 wouldnt 表示“坚决地拒绝”. I wont listen to your nonsense./We urged him to take a rest, but he wouldnt hear of it. 考点二、考点二、情态动词表情态动词表“可能性可能性”的用法：的用法： 1. can 表可能性，含有惊讶、
12、怀疑、不相信的语气，常用在否定句、疑问句、感叹句中，意为“可 能” ；can be 用于推测某人或某物一时的情况，意为“有时候会” ；could 表轻微的怀疑或委婉的看 法。 Can what he said be true? /What can he possibly mean? It can be very cold here at night. /The boy can be very annoying. His story could be true, but I hardly think it is. 注意：can 表示“可能性” ，有时也可用在肯定句中，但表示的是理论上的可能性，不
13、涉及是否真 的会发生。 The invention can be improved./The word “bank” can have several meanings. 2. may 表可能性，用于推测，暗指不确定，不用于疑问句，在疑问句中表示“可能”时，通常用 be likely to 或 do you think 结构；当句中出现 I am afraid, I am not sure 等表示不确定含义时，常选 用 may 或 might；may 表示的可能性比 might 大一些。3It is feared that many workers may lose their jobs th
14、is winter. /I am afraid he may be waiting for you. Is she likely to come this afternoon?3. must 可以表示推测，只能用在肯定句中，表示“一定”或“必定”之意，其否定形式是 cant/couldnt，意为“不可能” 。Must be doing 表示“现在肯定正在做” 。Whose new bike can it be? - It must be Liu Dongs. I know his father has just bought him a new one. You look happy. You
15、 must be having a good time. He cant be in Beijing now because I have seen him just now. 4. should 表示期待，用于表达合理的推断（“应该）或明显的结果（可能） ，所期待的事是事实。 It is three oclock, the football game should begin now. Mary took dancing lessons for years; she should be an excellent dancer. 注意：词组 be supposed to, be meant t
16、o 均有“应该；必须”等情态含义。 Everybody is supposed to wear a seat belt in the car. 考点三、情态动词考点三、情态动词+不定式的完成式不定式的完成式 “情态动词+不定式的完成式”在高考中出现的频率也相当高，其中尤以 must have done 出现次数 最多。下表是“情态动词+不定式的完成式”的结构和含义。结构含义could have done过去可以做而实际上没做。 “本来可以做” 。 表推测，过去可能做了某事cant /couldnt have done过去不可能发生的事情，是 must have done 的否定式。may/might have done对过去发生的行为的推测。 “可能会做” 。must have done对过去已发生的行为的推断。 “一定已做” 。need have done本来需要做而实际上已做了。 “本有必要做” 。neednt have done本来不需要做而实际上没做。 “本不
