1、情态动词用法,情态动词的语法特征,2) 情态动词不能单独做谓语, 后面只能接动词原形，ought to和have to除外，。,3) 情态动词没有人称, 数的变化, 但有些情态动词, 如can、will、have to、may等有过去式。,1）情态动词表说话人的某种感情或语气，对某一动作或状态的某种态度。,1) Some of us can use the computer now, but we couldnt last year.2) Can she be in the computer center?3) I though what he said could not be true.4
2、) Can/Could I use your dictionary?5) Could you lend me a hand?,1.表能力,意为“能，能够”，can指现在，could指过去。,3. 表示“请求” “允许”(表请求时，口语中常用 could 代替 can 使语气更委婉，回答时用can),2. 表示推测，意为“可能”“或许”，用于疑问句或否定句，cant和couldnt意为“不可能”。,1. can 与could,4. can 用于疑问句或否定句中时，表惊异、不相信等，意思是“可能、能够”。,6) How can you believe such a liar like him?,5
3、. cant/ couldnt have done 表示对过去情况的否定推测,意为“过去不可能做过某事”,7) Susan cant have written a report like this.8) She cant have gone to school, it is Sunday .,6. can/could have done表对过去的推测，意为“过去可能做了某事”。 could have done还可以表示对过去能做而未做的事情感到惋惜，意为“本能够做某事可事实上未做”,9）Its a pity. Your class could have got the first prize.
4、10）Where can Mary have gone?,can表示“能够”时与短语be able to同义，但can只用于一般现在时或过去时，而后者可用于各种时态。另外，can表示个人有某种能力，而be able to表示某人通过努力、克服困难做成某事，相当于succeed in doing sth.；,can/be able to,Michael _ be a policeman, for hes much too short. A. neednt B. cant C. should D. may2. Mr. Bush is on time for everything. How _ it
5、 be that he was late for the opening ceremony? A. can B. should C. may D. must3. - I stayed at a hotel while in New York. - Oh, did you? You _ with Barbara. A. could have stayed B. could stay C. would stay D. must have stayedMy sister met him at the Grand Theater yesterday afternoon, so he _ your le
6、cture. A. couldnt have attended B. neednt have attended C. mustnt have attended D. shouldnt have attended,B,A,A,A,5. Theres someone outside. Who _it be? A. can B. need C. may D. must6. -Is Jack on duty today? -It _ be him. Its his turn tomorrow. A. mustnt B. wont C. cant D. neednt7. It is usually wa
7、rm in my hometown, but it _be rather cold sometimes. A. can B. need C. dare D. must8. The fire spread through the hotel very quickly, but everyone _ get away. A. were able to B. would C. was able to D. could,A,C,A,C,2. may 与might,1. 表示“许可”或“请求”，有“可以”的意思，口语中 常用 might 代 may ,表示委婉语气。 否定回答时用“must not”表“
8、禁止，阻止”， 不用 “may not”. “may not” 表示“可能不” 。,Eg: 1)- May I watch TV after supper? - Yes, you may. / No, you mustnt. 2) Today is Sunday. She may not in her office now.,2. 表示可能性。 意为“或许，可能” might 比 may 可能性小。,Eg: 1) The girl might be sleeping this time of day. 2) They may be in the library now.,4. may/ mig
9、ht as well + 动词原形 “还是的好” “不妨干某事”,Eg: You may as well go and have a look.,3.may/might have done 表示对过去发生过的事情的推测，意为“可能已经做过某事”,Eg: I cant find my sunglasses. I may/might have left them in your office.,1.Sorry Im late. I _ have turned off the alarm clock and gone back to sleep again. A. might B. shouldC.
10、 can D. will2.Peter _ come with us tonight, but he isnt very sure yet. A. must B. may C. can D. will,A,B,3. will 与would,1. 用于第二人称的疑问句中，表“请求、建议”等，用 would 比用will 委婉，客气些,Eg: 1)Will you lend me your book? 2) Would you like a cup of tea?,2. 用于表示意志或意愿，意为“会，愿意” 。will 指现在，而 would 指 过去。用于否定句中，表示“不会、不肯、不乐意”。,
11、Eg: 1) I wont do that again. 2) They said that they would help us. 3) No matter what I said, he wont listen to me.,3.表示习惯性动作。 译作 “总是、惯于”， will 指现在常常，would 指过去常常。,Eg: 1)This man is strange. He will sit for hours without saying anything. 2) Mary will keep asking some silly questions. 3) Every evening,
12、 she would sit by window, deep in thought. 4) We would sit around Grandpa after supper, listening to his stories.,If you _ wait here for another 5 minutes, our manager will come back. A. should B. will C. need D. must2. When he was there, he_ go to that coffee shop at the corner after work every day
13、. A. would B. should C. had better D. might,B,A,4. should与ought to,1. ought to比should语气更重。两者都用于表劝告、建议。 意为”应该、应当”。但在疑问句中常用should。ought to的否定式为oughtnt to或ought not to。,Eg: I should help her because she is in trouble. You ought to take care of the baby. Should I open the window? What should we do next?
14、,2. 两者都可表示推测，表示很大的可能性。意为 “可能、按理该”,Eg: 1) Its 7 oclock, he should be at home. 2) They should have arrived by now.,3. ought to/should have done 本应该干某事可事实未干 oughtnt to/shouldnt have done本不该干某事可事实 却干了,Eg: You should have invited me to the party yesterday. You are right. I Should have thought of that. Yo
15、u shouldnt have eaten all the cakes in one day.,4. Should可以用来表示说话人的惊奇等情感，意为“竟然，居然”,Eg: 1) Its surprising that Mary should love such a person. 2) Its unbelievable that the boy should sing such a beautiful song.,1.You cant imagine that a well-behaved gentleman _ be so rude to a lady. A. can B. should
16、C. may D. must2. - When can I come for the photos? I need them tomorrow afternoon. - They _ be ready by 12:00 A. can B. should C. might D. need3. We _ last night, but we went to the concert instead. A. must have studied B. might study C. ought to have studied D. would study,B,B,c,5. shall,1. Shall用于
17、第一、三人称的疑问句中，表示说话人征求对方的意见或请求。,Eg: 1) Shall we begin our discussion? 2) Shall I change the clothes for the child? 3) Shall Tom go there with me tomorrow? 4) Henry is waiting outside. Shall he come in?,2. Shall用于二、三人称的陈述句，表示说话人 的允诺、警告、命令、威胁等语气。,Eg: 1)You shall get an answer from me tomorrow. 2) He shal
18、l be punished. 3) You shall go with me. 4) Tell Jerry that he shall get a gift if he behaves well.,Chairman Zhang, many people want to see you. _they wait here or outside? A. shall B. can C. should D. may2. You _use my bike if you can return it to me before Ileave here. A. should B. shall C. need D.
19、 must3. You _be punished if you break the rule. A. shall B. should C. need D. must,A,B,A,must/haveto/need,1.must用于一般问句中,肯定回答用must,否定回答用neednt或dont have to，意为“不必”。mustnt表示“禁止，不允许”, MustIfinishallhomeworkatatime?,Yes, you must. No,youneednt/dont have to.,I dont like this TV set. We must buy a new one.
20、 Mother was out, so I had to look after the shop.,2.表示“必须”这个意思时，must和haveto稍有区别。must着重说明主观看法，haveto强调客观需要。另外，haveto能用于更多时态。,Youmustbethenewteacher. Hemustbejoking. Thereisnobodyhere.Theymusthaveall gonehome.,3.must表示对某人某事的肯定猜测, 作“准是”, “一定” , 用于肯定句中。对过去发生的事情作肯定判断用must have done，意为过去一定已经做过某事。,Why must
21、 you always interrupt me?If you must smoke, do it outside, pleaseWhy must it rain on Sunday?,4. must表示与说话人愿望相反，翻译成“偏要，硬要，非要”,5.注意对need问句的回答: -Need I finish the work today? -Yes, _. No, _. No, _.,you must,you neednt,you dont have to,-Must we do it now? -No, you _.,neednt(dont have to),【考例】The boss ha
22、s given everyone a special holiday, so we _ go to work tomorrow. (上海 2007春)A. cant B. mustntC. neednt D. shouldnt【点拨】考查情态动词。根据题意, 可知这里表示“没有必要”, 故只能选C项。,【考例】What do you think we can do for our aged parents?You _ do anything except to be with them and be yourself. A. dont have to B. oughtnt toC. mustn
23、t D. cant 【点拨】根据题意“除了和他们呆在一起做你自己外, 没有必要做任何事情。”可知这里选择dont have to表示“不必”。故选A项。,【考例】 -Jane has just come back from China and she looks happy.- She _ her trip very much.must enjoy B. must have enjoyedC. may enjoy D should have enjoyed,【考例】 You _ return the book now, you can keep it until next week if yo
24、u like.cant B. mustntC. neednt D. may not,【考例】Where is Dad, Mary? He _ the flowers in the garden.must water B. must be wateringC. Must have watered D. watered,【考例】-Whats the matter with the man hanging his head there? -Well. If you _know, he was caught stealing my bike.must B. may C. can D. shall,情态
25、动词表推测用法小结,情态动词 + have done这是历年高考热点之一，可表示“推测、责备、怀疑”等多种意义。,一、表示对过去事情的推测或估计,1. must have done “过去肯定已经做了某事” 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
26、已经做了某事” eg: The ground is very dry, so it cant have rained last night注：在疑问句中 can/could 表示对过去情况的疑问性 推测，“可能已经了吗？” eg: Someone must have broken into our bedroom, Who could have done it?,二、表示对过去所发生事情的遗憾或责备,1. should/ought to have done “过去本应该做而没做” eg: I really regretted wasting the hours when I should ha
27、ve studied hard, but it was too late.2. shouldnt/oughtnt to have done “过去本不应该做的事却做了” eg: 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” eg: He could have worked out the problem.,4. neednt have done “原本不必做的事却做了” eg: Your home is not far from your school, so you neednt have left in such a hurry.,5. Would like to have done “本打算做某事但没做成” eg: I would like to have come to visit you, but I had to look after my sick mother at home.,
