情态动词包括情态动词的基本用法及其推测含义虚拟语气.docx

1、情态动词包括情态动词的基本用法及其推测含义虚拟语气 情态动词的用法情态动词有can (could), may (might), must, have to, shall (should), will (would), dare (darent,dared), need (neednt,needed), ought to,used to等。情态动词无人称和数的变化；不能单独使用 ,必须与其后的动词原形构成谓语。可以有推测意义 ,也可以没有推测意义。不同的“肯定程度可按以下层次排列： 1.He is at home. (事实) 2.He must be at home.非常肯定的推断 3.He c

2、ould be at home.很可能 4.He ought to be at home.很可能 5.He may be at home.仅仅可能而已 6.He might be at home.或许, 非常不确定 7.He might not be at home.也许不在家 8.He may not be at home.比might可能 9.He couldnt be at home.很可能不在家 10.He cant be at home.一定不在家一、can, could(1).can 的用法1.能力(能做某事): Two eyes can see more than one.2.表

3、示客观可能性客观原因形成的能力可以 ,可能。1) Theyve changed the timetable, so we can go by bus instead.2) This hall can hold 500 people at least.3.一时的可能性(有时可能) Children can be very trying(令人厌烦的;难受的).4.同意、允许(可以) Can I come in?在这里can 和may的意思差不多。口语中用can更多。5.用于疑问句和否认句中 ,表示惊讶、不相信等可能, 能够1) What can he mean? 他能够是什么意思呢？2) He c

4、ant be more than thirty. 他不可能在三十以上。后面有时跟完成形式或进行形式1) You cant have forgotten me. 你不可能已经忘记我了。2) If he said that, he cant be telling the truth. 如果他这样说 ,他讲的不可能是真话。3) What on earth can he be doing? 他此刻能在干什么呢？(2).could 的用法1.作为can的过去式 ,表示过去情况：a.能力：Lanny could run and was a good tennis player.这时可以用was/were

5、able to 表示同样的意思：b.可能性(可以 ,可能)：1) It was so dark we could see nothing. 2) He said he couldnt come.2.用来代替can,说明现在的情况a.婉转地提出请求、想法等：1) Could I borrow your book? 2) I could come early, if necessary.3) I couldnt be happier. 我不能再快乐了。b.用于疑问句及否认句 ,表示惊异、不相信等(推测性用法)：1) Could this be true?2) The money has disap

6、peared. Who could have taken it?3) Surely nothing could be going on there so late at night.3.could+完成形式可用来谈过去情况：a.表示那时“不可能 ,代表can的过去式：1) She couldnt have been more than sixteen at that time.2) We could not have heard them because of the noise from the river.b.表示那时“本来可以、“差点就要等：1) I could have lent yo

7、u the money. Why didnt you ask me?2) Her husband could have told her, but he did not choose to.(3).与其他情态动词的比拟1Can you lift this heavy box? 2He was able to (could) run very fast. a.表示能力 ,此时可用be able to代替。She wasnt able to (couldnt) answer the question.b. Can只有一般现在时和一般过去式；而be able to那么有更多的时态。Ill not b

8、e able to come this afternoon. c.当表示“经过努力才得以做成功某事时应用be able to ,was / were able to : “设法做成某事 相当于managed to do sth. succeeded in doing sth. 不能用Can。如：He was able to go to the party yesterday evening in spite of the heavy rain.d.表示请求和允许时可与may互换。- Can I go now? - Yes, you can. / No, you cant.e.在疑问句中还可用c

9、ould, might代替 ,不是过去式 ,只是语气更委婉 ,不能用于肯定句和答语中。- Could I come to see you tomorrow? - Yes, you can. ( No, Im afraid not. )1) A computer _ think for itself; it must be told what to do. A A. cant B. couldnt C. may not D. might not2) The fire spread through the hotel very quickly but everyone _ get out. D A

10、. had to B. would C. could D. was able to3) They will _ run this machine on their own in three months. DA. can B. could C. may D. be able to4) That big cinema _ seat 2,000 people. AA. can B. should C. ought to D. is able to二、 may, might (1).may的用法1.表示“允许： 1) May I have a word with you? 2) You may do

11、 exactly as you like.2.用在陈述句中表示“可能： 1) It may be a new species.2) A fool may give a wise man counsel(劝告). 傻子也可能给聪明人出主意。3.用在某些状语从句中：1) Write to him at once, so that he may know in time.2) Shut the window for fear that it may rain.4.用来表示祝愿1) May you enjoy many years of health and happiness.2) May God

12、bless you! 愿上帝赐福于你！5.用于may as well, 意为“不妨：1) Catherine, you may as well come too.2) If that is the case, I may as well try. 既然如此 ,我不妨试一试。(2).might 的用法1.用作may的过去式：a.表示“可以： 1) I asked her if I might call and see her. 2) I thought you might stay with us.b.表示“可能：1) He thought it might be wise to try his

13、 luck there.2) It was careful not to look at him. He might have seen the surprise in my eyes.c.用在某些状语从句中：He died so that others might live.2.用来代替may ,谈现在的情况 ,口气比may 更婉转些。a.表示“可以： 1) Might I borrow your umbrella? 2) I wonder if I might use your phone.b.表示“可能 ,“或许 ,比may所表达的可能性较低：1) It might be worth t

14、hinking about. 它可能值得考虑。2) I might have come to a wrong conclusion. 我可能得出了错误的结论。3) He might be expecting an answer from you. 他可能正期待这你的答复。3.用might+完成形式谈过去的情况a.“或许, “本来可以 ,表示与事实相反1) They might not have considered me as their friend.2) A lot of man died who might have been saved.b.用于might as well(和may a

15、s well意思相同 ,表示“不妨The buses are so expensive these days, you might as well get a taxi.(3).比拟may与might1.表示请求和允许。might比may语气更委婉 ,而不是过去式。might, could 比拟委婉, 一般多用于疑问句.can, may 表达的语言比拟随便. 否认答复时可用cant或mustnt ,表示“不可以 ,禁止。1) -Might/ May I smoke in this room? - No, you mustnt.2) - May/Might I take this book ou

16、t of the room? - Yes, you can. (No, you cant / mustnt. )用May I.？征徇对方许可时比拟正式和客气 ,而用Can I.？在口语中更常见。2. may可用于祈使句 ,表示祝愿。 1) May you succeed!3.表示推测、可能性不用于疑问句。might不是过去式 ,它所表示的可能性比may小。1) He may /might be very busy now.2) Your mother may /might not know the truth.3) Could I borrow your dictionary? Yes, of

17、 course you _. C A. might B. will C. can D. should4) Might I watch TV after supper? Yes, you _. A A. may B. must C. might D. can三、must, have to(1).must的用法1.表示“必须、“一定要、“得多指现在或将来情况：1) We must call the doctor. 2) Im afraid I must be going.2.mustnt 表示“一定不要：1) Of course she mustnt leave us. 2) You mustnt

18、 walk on the grass.3.表示“偏要 ,“偏偏做或发生不愉快的事)1) After I gave her my advice, she must go and do the opposite.2) Why must she be so angry with me? 为什么她偏偏对我生气？ 4. must表示推测、可能性多用于肯定的陈述句Judging by the smell, the food must be good.后面可跟完成形式或进行形式：1) The article must have been written by a woman. 2) He must be w

19、orking very hard. (2).与其他情态动词的比拟1. must表示必须、必要,在答复引出的问句时 ,如果是否认的 ,不用mustnt (禁止,不准),而用neednt, dont have to (不必).- Must we hand in our exercise books today? - Yes, you must.- No, you dont have to / you neednt.2. must是说话人的主观看法 ,而have to那么强调客观需要。Must只有一般现在时 , have to 有更多的时态形式。1) His play isnt interestin

20、g, I really must go now.2) I had to work when I was your age.四、dare, need(1).need 的用法1. need用作情态动词主要用于否认句和疑问句中 ,表示“不必1)You neednt clean the windows. They arent dirty.2) It neednt be talked about. 不必谈到它。 3) Need you have paid so much? 你必须付这么多钱吗？ 4) Do you think you need tell her about it?2.need的虚拟用法:

21、 neednt have done“本不必； neednt be doing“本不必1) You neednt have bought it. 你本不必买它的。 2) You neednt be standing here in the rain. 你本不必站在这儿的雨中。(2).dare的用法1. 作情态动词时表示“敢,但可有过去式dared, 主要用于否认句和疑问句：1) He darent ask his boss for a day off. 他不敢向老板请一天假。2) No one dared speak of it.3) How dare you ask me such a que

22、stion? 你怎么敢问我这样的问题。4) Dare you do it? -I darent do it.2. 用于I dare say (我猜想, 或许, 可能I dare say he will say. 或许他会说的。(3).dare和need异同：1.dare和need当情态动词用时：a.无人称和数的变化; b.后接动词原形, 尤其用于否认句及疑问句中; 可用在if/whether之后; 或与hardly, never, no one, nobody连用; c.常以neednt和darent的形式出现;；d. dare有其过去式dared。1) If we dared not go

23、there that day, we couldnt get the beautiful flowers.2) I darent ask her for a rise. 我不敢请求她加薪.3) How did you dare to tell her that? 4) I wonder whether he dare stand up in public. 5) I wonder whether he need send it immediately.6) I need hardly tell you that the work is dangerous. 我几乎不必告诉你这个工作是危险的。7

24、) You neednt finish that work today.2.当实义动词用时多用于肯定句 ,有人称、时态和数的变化。在肯定句中 ,dare后面常接带to的不定式。在疑问句和否认句中 ,dare后面可接带to或不带to的不定式。而need后面只能接带to的不定式。(sb.) need to do；dare to do；(sth.) need to be done；(sth.) need doing 1) I dont know how she dares to wear that dress. 我不知道她怎么敢穿那件长裙。2) He doesnt dare (to) answer.

25、 3) He needs to finish his homework today. 他今天需要完成他的家庭作业。4) Do you need any help?5) The garden doesnt need watering at the moment. 五、shall, should(1).shall 的用法1.shall表威胁、警告、命令、承诺 ,用于第二、第三人称。1) He shall be punished if he disobeys. 他假设不服从就要受到惩罚。 2) You shall have my answer tomorrow. 你明天可以得到我的答复。3) She

26、 shall get her share. 她可以得到她的一份。2.表征询意见 ,用于第一、第三人称 ,并用于疑问句。1) Shall I get you some fresh coffee, Linda? 琳达 ,我给你取些新鲜的咖啡好吗？2) What shall we do this evening? Shall we go to the theatre? 今晚我们干什么？去看戏好吗？(2).should的用法1.表义务, 可用于各种句式,通常指将来或现在。1) You should do what your parents tell you. 你应该干你的家长告诉你的事。2) He s

27、hould do some work, but he doesnt want to. 他应该干些活 ,但他不想干。3) You shouldnt feel so unhappy over such trifles. 对这种小事,你不应该感到这么不快乐。4) You shouldnt be sitting in the sun. 你不应该坐在阳光下。2.用于第一人称问句 ,表征询意见。 Should I open the window?3.表感情色彩 ,意为“竟然。1) Why shouldnt you invite him？2) I dont see why we shouldnt make

28、friends? 我不明白为什么我们竟不能成为朋友?4. should的虚拟和推测用法a.表推测 ,“按理应该。1)The film should be very good as it is starring first-class actors.2) I should know her among a thousand.b.表虚拟 ,“本来应该 或“应该。1) He looks very ill. He should have stayed at home.2) I suggest that you should stay here as if nothing had happened.3)

29、 If he should drop in, give him my message.六、will, would(1).will的用法1.表意愿, 主要用于第一人称。would指过去将来1) I wont argue with you. 2) I said I would do anything for him.2.表拒绝, 用于否认句。would指过去将来。1) The doctor knows I wont be operated on. 大夫知道我不想做手术。如主语是物, 那么意为“不起作用。 2) The drawer wont (wouldnt) shut. 抽屉关不上了。3) My

30、 fountain pen wouldnt write. 我的自来水笔不能写字了.3.表请求 ,指将来 ,用于疑问句。would更客气1) Will you dine with me tomorrow? 明天同我一道吃饭好吗？ 2) Would you mind closing the door? 你介意关门吗？4.表猜想 ,指现在或将来；用于进行式时指现在；用于完成式时指过去 ,用于二、三人称。1) This will be the school, I believe. 2) They will be waiting. 他们一定在等我们。3) You will have heard the

31、news, Im sure. 我想你大概听到了这个消息。5.有时will 表难免。1) Boys will be boys. 男孩子毕竟是男孩子。 2) Accident will happen. 事故难免发生。(2).would 的用法1.表过去习惯性的动作：1) Occasionally they would go out and paint pictures. 偶尔他们会出去画画。2) Now and then a black bird would call. 偶然黑鸟会叫几下。2.表示对过去事情的推测 ,“大概; 想必是:1) That would be in 1976, I think. 我想那大概是在1976年。 2) The per