1、Grammar,Suqian Sarbrina,情态动词用法,Whats the definition of modal verbs?,情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词,但不能单独作谓语, 只能和其他动词原形构成谓语。,一.情态动词的语法特征,1） 情态动词 不能单独做谓语，除ought 和have 外，后面只能接不带to 的不定式。,2） 情态动词没有人称，数的变化，但有些情态动词，如can、will也有一般式和过去式的变化。,3） 情态动词的“时态”形式并不是时间区别的主要标志，不少情况下，情态动词的现在式形式和过去式形式都可用来表示现在时间、过去时间和将
2、来时间。,(1). We use modal verbs to talk about:,1. Ability （能力） 2. Obligation （义务） 3. Certainty （可能性） 4. Permission （允许）,二情态动词的语法功能,(2).We also use modal verbs to:,5. Make requests（提出请求） 6. Make suggestions（提出建议） 7. Make offers（提供帮助） 8. Give advice（提出意见）,情态动词,1. can could be able to,4. shall,2. may migh
3、t,三常见情态动词的基本用法,5. must have to,3. will would,7. need dare,6. ought to should,8. 情态动词+have done,情态动词,1. can could be able to,3. shall,2. may might,The usage of some common modal verbs,4. must have to,5. 情态动词+have done,1.can 1)表能力 can表能力时意味着凭体力或脑力或技术等可以无甚阻力地去做某事。 I can climb this pole. He is only four
4、 , but he can read. Fire cant destroy gold.,can 和could：,2)表推测、可能性(用于否定与疑问结构中) Can the news be true? It cant be true. What can he possibly mean? 他可能是什么意思?,3)表示请求或允许(和may意思相近)常见于口语。Can (May) I come in ? 我能进来吗? Can I smoke here ? 我可以在这里抽烟吗?,2) could的主要用法是：A. could 是can的过去式, 表示与过去 有关的能力和推测: eg. We all k
5、new that the young man couldnt be a doctor.B. could可以代替can表示请求、允许。可表示委婉客气的提出问题或陈述看法,Could you lend me your dictionary? Could I use your bike? Yes, you can. Im afraid I couldnt give you an answer today.,Attention:,can/be able to区别:,can表示与生俱来的能力或一种客观可能，而be able to更加强调通过后天的学习和努力获得的能力，或者在某个客观的场合和背景下，能做到
6、的事情。,I cant swim, but I am sure I will be able to swim through more practicing.,表示特定的某一过去能力或表示成功地做了某事时，只能用was/were able to， 不能用could。,He _ flee Europe before the war broke out.,Note：,was able to,A big fire broke out in ABC hotel yesterday. Luckily, everyone _ run out of the building.,was able to,2.
7、She _ speak both English and French.,can,I cant thank you too much.,can never/canttoo表示“无论怎样也不过分”，“越越好” 。,你过马路的时候再小心也不为过。,You cant be too careful while crossing the road.,She couldnt but agree to my idea. I cant thank you enough. The film couldnt be any worse.,Can或could 的否定形式构成习惯短语 Cant.too. Cant en
8、ough.无论怎样也不过分 Cant (help) but do不得不做，只好做 Cant help doing 情不自禁 Cant help it 没有办法 Cant .+比较级 再不过了（表示最高级）,May I watch TV after supper? Yes,_./ No, _. Might I use your telephone? May I go home now? It may be true. She may come tomorrow. He might have some fever. May you succeed! May you have many more d
9、ays as happy as this one!,you may,You mustnt,允许,许可,禁止,阻止,Might比May的语气更委婉,表示可能性的推测,译为“大概,可能”用might时显得更加不肯定,用于祈使句表示祝愿,. May 和Might,A computer _ think for itself; it must be told what to do. A. cant B. couldnt C. may not D. might not,A,may _ can_,表主观“可能”,表客观“可能”,cannot_ may not_,不可能,可能不,may 和can,They_
10、be doing the experiment in the lab. Why？ Because the lights are still burning.,A.could B.can C.must D.would,will和would：,will当作情态动词时有以下用法:,If you give him time, Tom will talk and talk for hours.Every Saturday evening they will play chess together,表经常性，习惯性“老是、总是、终归是”,The door wont open.Ill do my best
11、to help you.Will you please give me a message when you see him?-Write to me when you get home. -I will.,表示功能，译作“能”或“行”,意愿,2人称，询问对方意愿或向对方提出请求,回答祈使句,Would当作情态动词时有以下用法：Would you help us, please? When I had some trouble, he would encourage me. We all tried to stop him smoking in bed but he wouldnt liste
12、n.,过去的习惯,意愿“要；愿”,用于2人称，表示有礼貌的请求或邀请,Would 与 Used to do 区别 “过去常常”,Would-过去习惯的动作（现在有可能还有此习惯）Used to do -过去习惯的动作及状态（现在已经没有此习惯）,The old man _have a smoke under a big tree every afternoon after he finished his farm work.,would,可表示经常性、习惯性、倾向性。翻译为“经常、惯于、总是”。,shall和should：,1. shall用于征求对方的意见，表 “决心”Shall we go
13、 by train, Mom?妈妈，我们乘火车去好吗？（用于征求对方的意见） I shall go at once.我必须立即去。（表 “决心”）,1)用于第一、 三人称征求对方的意见， What shall he wear on the journey? Shall we dance? 2)shall 用于第二、三人称时表允诺，警告，命令，威胁。“必须，应该可以” If he passes the examination, he shall have a holiday. You shall have it back tomorrow.,3）用于第二、三人称用于法律法规条例等文件中的要求。“
14、应该、必须” Its required in our regulation that students shall go to school on time. Persons under 18 shant be employed in night work.,2. should表示义务、建议、劝告等，意为 “应该”。(ought to) Students should respect teachers.The boys shouldnt be playing football; they should be at school.Its 4:30,They should be in New Yo
15、rk by now.,劝告、建议,义务、责任,常规、常理的推测（正常情况下）按理应该,He ought to succeed, as he is so diligent. It is strange that it should be so hot today.I dont understand why she should have made such a mistake.Should it rain tomorrow, the meeting will be postponed.,居然，竟然,与疑问词连用，表示意外、纳闷、惊讶等 “究竟是，到底”,用于条件句中“万一”,- Whats th
16、e name?- Khulaifi. _ I spell that for you? Shall B. Would C. Can D. Might,Drill(小练),（10江苏）I havent got the reference book yet, but Ill have a test on the subject next month.Dont worry. You_ have it by Friday.A. could B. shall C. must D.may,解析：shall在第二人称中表示允诺，还可以表示强制，命令，威胁，警告。还有在法律条文中的要求或规定。,答案：B,You
17、 shall be punished for what youve done.,你一定会因为你的所作所受到惩罚。,must和 have to,1.must用于一般问句中,肯定回答用must否定式用 neednt或dont have to，做 “不必”, mustnt表示“禁止，不允许”, Must I finish all the work at a time?,Yes, you must.No, you neednt.,I dont like this TV set. We must buy a new one. There was no more bus. They had to walk
18、 home.,2.表示“必须”这个意思时，must 和have to 稍有区别。must着重说明主观看法，have to 强调客观需要。另外，have to 能用于更多时态。,You must be the new teacher. He must be joking. There is nobody here. They must have all gone home.,3.must表示对某人某事的猜测， 作“准是”，“一定” ，一般用于肯定句中。对过去发生的事情作肯定判断用must have done,How old are you, madam? If you must know, Im
19、 twice my sons age.,4. must表示“偏要，硬要”，指做令人不快的事情,need 与 dare,实义动词,情态动词,.可兼做行为动词的情态动词：need 、 dare,情态动词 (+动词原形),行为动词,.,need,dare,1.无人称和数的变化;,2.尤其用于：,*否定句及疑问句中;,*在if/whether之后;,*或与hardly, never, no one, nobody连用;,3.常以neednt 和darent 的形式出现;,4.dare有其过去时dared.,多用于肯定句;need to dodare to do need to be doneneed
20、doing,实义动词 vs 情态动词,肯定句,实,情,e.g. She needs to stay at home today.e.g. He dares to jump from the high wall.,e.g. She need stay at home today. e.g. He dare jump from the high wall.,疑问句,e.g. Does she need to stay at home today?e.g. Does he dare to jump from the high wall?,e.g. Need she stay at home toda
21、y? e.g. Dare he jump from the high wall?,实,情,否定句,Dare 作为实意动词的时候，否定句中的 to 可以省略,e.g.He doesnt dare (to) jump from the high wall.,实,e.g. She doesnt need to stay at home today.e.g. He doesnt dare to jump from the high wall,情,e.g. She neednt stay at home today.e.g. He dare not jump from the high wall.,表示
22、否定的情态动词的用法:部分情态动词的否定式是情态动词中的考点 之一。,mustnt 不准, 禁止 neednt 没必要 ( = dont have to ) cant 不能; 不可能 may not 不可以; 可能不 shouldnt 不应该 ( = ought not to ),Attention:,must have done 过去一定做过某事 cant have done 过去不可能做过某事 should ( ought to ) have done 过去本该做某事却没做 shouldnt ( ought not to ) have done 过去本不该做某事却做了,. 情态动词+hav
23、e done表示对已经发生事情推测、 责怪、后悔、遗憾等。,neednt have done 过去没有必要做某事而实际上却做了 could have done 过去本可以做某事却没做 might have done 过去可能已经做了某事,5. 情态动词+have done表示对已经发生事情推测、 责怪、后悔、遗憾等。,1. It must have rained last night, for the streets are wet. 2. He looks very happy. He might not have known the result. 3. He could not have
24、 done such a thing. 4. She didnt come to school yesterday. Can she have been ill? 5. They left here early and should have arrived by now.,情态动词表推测 对过去情况的推测,6. You might have written the letter without my reminding you of it. 7. The doctor could have avoided the accident 8. You should have finished th
25、e task yesterday. 9.I was really anxious about you,you shouldnt have left home without a word. 10.He ought not to have told me your secret,but he meant no harm.,过去本可能（不用may),过去本能够却没有,过去本应该却没有,过去本不该,过去本不该,1. The weather turned out to be fine yesterday. I_ the trouble to carry my umbrella with me.A. s
26、hould have taken B. could have taken C. neednt have taken D. mustnt have taken 2. -Ill tell Mary about her new job tomorrow.-You _her last week.A. ought to tell B. would have told C. must tell D. should have told,C,D,Practice,3. She _ have left school, for her bike is still here.A. cant B. wouldnt C
27、. shouldnt D. neednt 4. - I cant find my purse anywhere.- You _ have lost it while shopping.A. may B. can C. should D. would 5. - 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 stayed,A,A,A,表推测的情态动词句子的反意疑问句 He must
28、/may be in the room, isnt he? He cant be in the room, is he?He must have finished the work, hasnt he? He may have done the work last night, didnt he?He must have been caught in the heavy rain last night,_,wasnt he.,（10四川） 1. _ I take the book out?Im afraid not.A. Will B. May C. Must D. Need,考点：考查情态动
29、词。 解析：表请求可用情态动词can, may, could, might ,表允许用can, may. 句意为：“我可以将这本书带出去吗？”“恐怕不行”。故应选表请求的情态动词may。正确答案为B。,答案：B,(10陕西） 2. -May I take this book out of the reading room?-No, you . You read it in here. A. mightnt B. wont C. neednt D. mustnt,解析：考查情态动词。英语中用could，might表示询问或征求意见的问句中，肯定性应答要用can或may来代替could或might
30、，而may或might征求意见的问句否定应答时要用mustnt，表示禁止.故本题选D。,答案：D,（10湖南） 3. You_buy a gift, but you can if you want to. A. must B. mustnt C. have to D. dont have to,考点：情态动词 解析：dont have to 意为“没有必要”，符合语境，句意为：“你没有必要买礼物，但如果你想买的话，你也可以买。”,答案：D,（10浙江） 4. “You _ have a wrong number,” she said. “Theres no one of that name h
31、ere.” A. need B. can C. must D. would,考点：情态动词 解析：肯定猜测，用must,答案：C,（10全国） 5.Im afraid Mr. Harding _see you now. Hes busy. A. cant B. mustnt C. shouldnt D .neednt,解析：情态动词考查。结合语境，根据情态动词用于疑问或否定推测时，要用cant。,答案：A,6. I cant thank you too much for your kindness, because without your help I_have won the first
32、prize in the speech contest A.cant B.shouldnt C.might not D.couldnt 考查情态动词的虚拟语气的用法。意为，我再感谢你也不为过，没有你的帮助，我不可能在演讲比赛中获得第一名。根据句意可知，演讲比赛已经结束。Cant have done 不可能做了某事。 Shouldnt have done 本不应当做某事 might not have done 可能没有干某事，均不符合题意。,D,7 What sort of house do you want to have?Something big?-Well, it _ be bigtha
33、ts not important. A. mustnt B. neednt C. cant D. wont改错Mr. Li mustnt have gone to Shanghaibecause I saw him a few minutes ago.,B,cant,must表推测只用于肯定句, 否定句中表推测 用cant; mustnt 指 “禁止、不准”,8. -Where is my dictionary? I remember I put it here yesterday.-You _it in the wrong place. A. must put B. should have
34、put C. might put D. might have put 9. -Is John coming by train?-He should, but he _not. He likes driving his car.A. must B. can C. need D. may,D,D,表对过去可能性的推测。,10. A _ candle _ the faces of everybody in the room. They all looked tired.A. lit , lit up B. lit up , lit C. lighted, lit up D. lighted, lit11.There is a party tonight _ our new president, and I am _ to be invited.A. in honor; honored B. in place of; of great honorC. in great honor; in favor of D. in honor of; honored,D,C,
