高考情态动词的用法及区别

1、高中情态动词的用法及区别首先它是动词,而且不同于行为动词,行为动词表示的是可以通过行为来表达的动作(如写,读,跑,而情态动词只是表达的一种想法(如能,也许,敢。用法是:情态动词+行为动词原形例句:I can read this sentence in English.我能用英语读这句话。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。We can be there on time tomorrow.我们明天能按时去那儿。May I have your name? 我能知道你的名字吗?Shall we begin now?我们现

2、在就开始吗?You must obey the school rules.你必须遵守校规。情态动词数量不多,但用途广泛,主要有下列:can (could, may (might, must, need, ought to, dare (dared, shall (should, will (would,have (to ,had better.情态动词还有一个很重要的用法,即情态动词表推测情态动词表推测的用法小结(一情态动词表推测的三种句式1.在肯定句中一般用must (一定,may(可能,might / could(也许,或许。(1He must/may/might know the ans

3、wer to this question?他一定/可能/也许知道这个问题的答案。(2It is cold in the room. They must have turned off the heating.屋里很冷,他们肯定把暖气关了。2.否定句中用cant / couldnt(不可能, may not/might not(可能不。(1It cant/couldnt be the headmaster. He has gone to America.这不可能是校长,他去美国了。(2He may not/might not know the scientist.他也许不认识那位科学家。3.疑问

4、句中用can/could (能?。(1Could he have finished the task?他可能把任务完成了吗?(2Can he be at home now?他现在能在家吗?注:以上三种句式中情态动词的语气按程度都是依次递减的。Might, could并非may, can的过去式,而表示语气较为委婉或可能性较小。(二情态动词表推测的三种时态1.对将来情况的推测,用“情态动词+ 动词原形”。(1She must / may / might / could arrive before 5.5:00前她一定/可能/也许到。(2She must/may/might/could walk

5、miles and miles among the hills without meeting anyone.她一定/可能/也许会在山里一连走好几英里而遇不到一个人。2.对现在或一般情况的推测,用“情态动词+ be”,“情态动词+be doing”或“情态动词+ 动词原形”。(1He must / may / might / could be listening to the radio now.他一定/可能/也许正在听收音机。(2He cant ( couldnt / may ( might not be at home at this time.这个时候他不可能/可能不在家。(3Mr. B

6、ush is on time for everything .How can ( could he be late for the opening ceremony ?布什先生一向准时,这次开幕式他怎么可能迟到呢?3.对过去情况的推测,用“情态动词+ have +过去分词”。(1It must / may / might / could have rained last night .The ground is wet.地湿了,昨晚肯定/可能/也许下雨了。(2The door was locked. He can ( could not / may ( might not have been

7、at home .门锁着,他不可能/可能不在家。(3Can / Could he have gotten the book?难道他找到书了吗?注:情态动词should /ought to表推测时,意为“想必会,理应”但与“have +过去分词”连用时,则又可构成虚拟语气意为“本应该做某事却没做”。例如:(4Its seven oclock. Jack should/ought to be here at any moment.现在七点钟了,杰克理应随时到达。(推测(5She should / ought to have attended your birthday party, but she

8、 had to look after her mother in hospital. (虚拟她本该出席你的生日晚会的,可是她得在医院照顾她妈妈。(6Tom should not /ought not to have told me your secret, but he meant no harm. (虚拟汤姆本不该告诉我你的秘密,可是他并无恶意。情态动词有can (could, may (might, must, have to, shall (should, will (would, dare (dared, need (needed, ought to等。情态动词无人称和数的变化;不能单

9、独使用,必须与其后的动词原形构成谓语一、can, could1 表示能力(体力、知识、技能。Can you lift this heavy box?(体力Mary can speak three languages.(知识Can you skate?(技能此时可用be able to代替。Can只有一般现在时和一般过去式;而be able to则有更多的时态。Ill not be able to come this afternoon.当表示“经过努力才得以做成功某事”时应用be able to,不能用Can。如:He was able to go to the party yesterday

10、 evening in spite of the heavy rain.2 表示请求和允许。-Can I go now?- Yes, you can. / No, you cant.此时可与may互换。在疑问句中还可用could,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. 3 表示客观可能性(客观原因形成的能力。Theyve changed the timetable, so we can go by bus instead.T

11、his hall can hold 500 people at least.4 表示推测(惊讶、怀疑、不相信的态度,用于疑问句、否定句和感叹句中。Can this be true?This cant be done by him.How can this be true?二、may, might1 表示请求和允许。might比may语气更委婉,而不是过去式。否定回答时可用cant或mustnt,表示“不可以,禁止”。-Might/ May I smoke in this room?- No, you mustnt.- May/Might I take this book out of the

12、room?- Yes, you can. (No, you cant / mustnt. 用May I.?征徇对方许可时比较正式和客气,而用Can I.?在口语中更常见。2用于祈使句,表示祝愿。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.三、must, have to1 表示必须、必要。You must come in time.在回答引出的问句时,如果是否定的,不能用

13、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则强调客观需要。Must只有一般现在时,have to 有更多的时态形式。1.he play isnt interesting, I really must go now.2.I had to work when I was your age.3 表示推测、可能性(只用于肯定的陈述

14、句1.Youre Toms good friend, so you must know what he likes best.2.Your mother must be waiting for you now.四、dare, need1 dare作情态动词用时, 常用于疑问句、否定句和条件从句中, 过去式形式为dared。1.How dare you say Im unfair?2.He darent speak En glish before such a crowd, dare he?3.If we dared not go there that day,we couldnt get th

15、e beautiful flowers.2 need 作情态动词用时, 常用于疑问句、否定句。在肯定句中一般用must, have to, ought to, should代替。1.You neednt come so early.2. - Need I finish the work today?- Yes, you must. / No, you neednt.3 dare和need作实义动词用时,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。在疑问句和否定句中,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。1. I dare to s

16、wim across this river.2. He doesnt dare (to answer.3. He needs to finish his homework today.五、shall, should1 shall 用于第一人称,征求对方的意见。What shall we do this evening?2 shall 用于第二、三人称,表示说话人给对方的命令、警告、允诺或威胁。1. You shall fail if you dont work hard.(警告2. He shall have the book when I finish it.(允诺3. He shall b

17、e punished.(威胁六、will, would1 表示请求、建议等,would更委婉。Will / Would you pass me the ball, please?2 表示意志、愿望和决心。1. I will never do that again.2. They asked him if he would go abroad.3 would表示过去反复发生的动作或某种倾向。would表示过去习惯时比used to正式,且没有“现已无此习惯”的含义。1. During the vacation, he would visit me every other day.2. The wound would not heal.4 表示估计和猜想。It would be about ten oclock when she left home.七、should, ought to1 should, ought to表示“应该”,ought to表示义务或责任,比should语气重。1. I should help her because she is in trouble.2. You ought to take care of the