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英语语法大全整本收录(二十一)情态动词

发布时间:2012-10-31 05:11     浏览次数:

[标签:初中英语 初中英语语法 ]

   21. 情态动词   21.1 情态动词的语法特性 一) 情态动词不能示意正在产生或已经产生的事变,只示意等待或估量某事的产生。 二) 情态动词 除ought 和have 外,后面只能接不带to 的不定式。  三) 情态动词没有人称,数的变化,即情态动词第三人称单数不加-s。 四) 情态动词没有非谓语情势,即没有不定式,分词,等情势。   21.2 对比can 和be able to   一...

 

  21. 情态动词

  21.1 情态动词的语法特性

 一) 情态动词不能示意正在产生或已经产生的事变,只示意等待或估量某事的产生。

 二) 情态动词 除ought 和have 外,后面只能接不带to 的不定式。

 三) 情态动词没有人称,数的变化,即情态动词第三人称单数不加-s。

 四) 情态动词没有非谓语情势,即没有不定式,分词,等情势。

  21.2 对比can 和be able to

  一)can could 示意本领;可能 (过去时用could),

  只用于现在式和过去式(could)。be able to可以用于各种时态。

 They will be able to tell you the news soon. 他很快就能奉告你新闻了。

  二)只用be able to

 a. 位于助动词后。

 b. 情态动词后。

 c. 示意过去某时刻动作时。

 d. 用于句首示意前提。

 e. 示意胜利地做了某事时,只能用was/were able to, 不能用could。

 He was able to flee Europe before the war broke out.

 = He managed to flee Europe before the war broke out.

  注重:could不示意时态

  一)提出婉转的恳求,(注重在回答中不可用could)。

 --- Could I have the television on?

 --- Yes, you can. / No, you can't.

  二)在否定,疑问句中示意猜测或思疑。

 He couldn't be a bad man.  

 他不大可能是坏人。

  21.3 对比may和might

  一) 示意许可或恳求;示意没有掌控的猜测;may 放在句首,示意祝贺。

 May God bless you!

 He might be at home.

  注重: might 示意推测时,不示意时态。只是可能性比may 小。

  二) 成语: may/might as well,后面接不带to 的不定式,意为"无妨"。

 If that is the case, we may as well try.

  典型例题

 Peter ___come with us tonight, but he isn't very sure yet.

 A. must  B. may  C. can  D. will

 谜底B. 表可能性只能用may. 此句意可从后半句推出。

  21.4 对比have to和must

  一) 两词都是'必需'的意思,have to 示意客观的必要, must 示意语言人主观上的见解,既主观上的需要。

 My brother was very ill, so I had to call the doctor in the middle of the night. 我弟弟病得很利害,我只得午夜里把大夫请来。(客观上必要做这件事)

 He said that they must work hard. 他说他们必需高兴工作。(主观上要做这件事)

  二) have to有人称、数、时态的变化,而must只有一种情势。但must 可用于间接引语中示意过去的需要或任务。

  He had to look after his sister yesterday.

  三) 在否定结构中: don't have to  示意"没必要"

 mustn't 示意"制止",

 You don't have to tell him about it.  你不一定要把此事奉告他。

 You mustn't tell him about it. 你必定不要把这件事奉告他。

  21.5 must示意猜测

 一) must用在确定句中示意较有把握的猜测,意为"必定"。

 二) must表对如今的状况或如今正产生的事变的推测时, must 后面平日接系动词be 的本相或举动动词的进行式。

 You have worked hard all day.You must be tired.  你费力干一整天,必定累了。(对如今情形的猜测果断)

 He must be working in his office. 他必定在办公室工作呢。

 对比:

 He must be staying there. 

 他如今确定呆在那里。

 He must stay there.

 他必需呆在那。

 三) must 示意对已产生的事变的推测时,must 要接完成式。

 I didn't hear the phone. I must have been asleep. 我适才没有听到电话,我想必是睡着了。

 四) must示意对过去某时正产生的事变的猜测,must 后面要接不定式的完成进行式。

 ---Why didn't you answer my phone call?

 ---Well, I must have been sleeping, so I didn't hear it.

 五) 否定猜测用can't。

 If Tom didn't leave here until five o'clock, he can't be home yet. 要是汤姆五点才脱离这儿,他此时必定还未到家。

  21.6 示意猜测的用法

 can, could, may, might, must 皆可示意猜测,其用法以下:

  一)情态动词+动词本相。

 示意对如今或未来的情形的猜测,此时动词平日为系动词。

 I don't know where she is, she may be in Wuhan.

  二)情态动词+动词如今进行时。

 示意对如今或未来正在进行的情形进行猜测。

 At this moment, our teacher must be correcting our exam papers.

 这时候,咱们教师想必在修正试卷。

  三)情态动词+动词完成时。

 示意对过去情形的猜测。

 We would have finished this work by the end of next December.

 来岁12月尾前咱们极可能已完成这项工作了。

 The road is wet. It must have rained last night.

 地是湿的,昨天晚上必定下雨了。

  四)情态动词+动词的如今完成进行时。

 示意对过去正在产生事变的猜测。

 Your mother must have been looking for you.

 你妈妈必定不停在找你。

  五)猜测的否定情势,疑难情势用can't, couldn't示意。

 Mike can't have found his car, for he came to work by bus this morning.

 迈克必定尚无找回他的车,由于早上他是坐公共汽车来上班的。

 注重:could, might示意推测时不示意时态,其猜测的水平不如can, may。

  21.7 情态动词+ have +过去分词

  一) may(might) have + done sth, can (could) have + done sth 示意过去,猜测过去时候里可能发生的事变。

 Philip may (might) have been hurt seriously in the car accident.

 Philip can (could) have been hurt seriously in the car accident.

  二) must have +done sth,对过去时候里可能发生的事变的猜测,语气较强,拥有"确定","谅必"的意思。

 ---Linda has gone to work, but her bicycle is still here.

 ---She must have gone by bus.

  三) ought to have done sth, should have done sth

 本应当做某事,而事实上并无做。否定句示意"不该做某事而做了"。

 You ought to (should) have been more careful in this experiment.

 He ought not to have thrown the old clothes away.(事实上已扔了。)

 ought to 在语气上比should 要强。

  四) needn't have done sth  本没需要做某事

 I dressed very warmly for the trip, but I needn't have done so. The weather was hot.

  五) would like to have done sth  本计划做某事 

 I would like to have read the article, but I was very busy then.

  21.8 should 和ought to

 should 和ought to 都为"应当"的意思,可用于各种人称。

 ---Ought he to go?

 ---Yes. I think he ought to.

 示意要求,下令时,语气由 should(应当)、had better最佳)、must(必需)渐强

  21.9 had better示意"最佳"

 had better 相当于一个助动词,它只有一种情势,它后面要跟动词本相。

 had better do sth

 had better not do sth

 It is pretty cold. You'd better put on my coat.

 She'd better not play with the dog.

 had better have done sth示意与究竟相反的效果,意为"原先最佳"。

 You had better have come earlier.

  21.10 would rather示意"甘心"

 would rather do

 would rather not do

 would rather… than…  甘心……而不愿。

 还有would sooner, had rather, had sooner都示意"甘心"、"宁肯"的意思。

 If I have a choice, I had sooner not continue my studies at this school.

 I would rather stay here than go home. = I would stay here rather than go home.

  典型例题

  ----Shall we go skating or stay at home?

  ----Which ___ do? 

  A. do you rather  B. would you rather  C. will you rather  D. should you rather

  谜底B。本题考察情态动词rather的用法,would rather +do sth 意为"甘心",本题为疑问句,would 提早,以是选B。

  21.11 will和would

 注重:

 一)would like; Would like to do = want to 想要,为固定搭配。

 Would you like to go with me?

 二)Will you…? Would you like…? 示意确定含意的恳求奉劝时,疑问句中一样平常用some, 而不是any。

 Would you like some cake?

 三)否定结构顶用will,一样平常不用would, won't you是一种婉转语气。

 Won't you sit down?

  21.12 情态动词的回答体例

 问句 确定回答 否定回答

  Need you…?  Yes, I must. No,I needn't

  Must you…? /don't have to.

  典型例题

  一)---Could I borrow your dictionary?

 ---Yes, of course, you____. 

 A. might B. will  C. can  D. should

 谜底C.could示意婉转的语气,其实不为时态。答语中of course,示意确定的语气,许可或人做某事时,用can和 may来表达,不能用could或might。温习: will 与you连用,用来提出要求或下下令。should与you 连用,用来提出劝告。

  二)---Shall I tell John about it?

 ---No, you ___. I've told him already.  

 A. needn't  B. wouldn't  C. mustn't  D. shouldn't

 谜底A。needn't 没必要,不用。 wouldn't 将不, 不会的。 mustn't 制止、不能。 shouldn't 不应当。本题为不需要,没必要的意思,运用needn't。

  三)---Don't forget to come to my birthday party tomorrow.

 ---______.

 A. I don't  B. I won't  C. I can't D. I haven't

 谜底B. will既可算做情态动词,表恳求、建议、也可作为实义动词表"意愿、意志、决心",本题示意决心,选B。

  21.13 带to 的情态动词

 带to 的情态动词有四个:ought to, have to, used to, be to, 如加之have got to ,(=must), be able to,为六个。它们的疑难,否定情势应予以注重:

 Do they have to pay their bill before the end of the month?

 She didn't use to play tennis before she was fourteen.

 You ought not to have told her all about it.

 Ought he to see a heart specialist at once.?

 ought to 自身作为情态动词利用。其他的词作为实义动词利用,变疑难,否守时,须有do 等助动词帮忙。

  典型例题

 Tom ought not to ___ me your secret, but he meant no harm. 

 A.have told B.tell C.be telling D. having told

 谜底A。因为后句为过去时,奉告隐秘的动作又产生在其前因,此地运用过去完成时,但它在情态动词 ought to 后,以是用have。

  21.14 对比need和dare

 这两词既可做实义动词用,又可做情态动词用。作为情态动词,二者都只能用于疑问句,否定句和前提句。 need 作实义动词时后面的不定式必需带to,而dare作实义动词历时, 后面的to 经常可以被省略。

  一) 实义动词: need (必要, 要求)

 need + n. / to do sth

  二) 情态动词: need,只用本相need后加do,否定情势为need not。

 Need you go yet?

 Yes, I must. / No, I needn't.

  三) need 的被动含意:need, want, require, worth(形容词)后面接doing也可以示意被动: 

 need doing = need to be done

  到此为止整本书就收场了,谢谢人人的支撑,期望本书能给你们带来匡助.祝人人的英语蒸蒸日上.

  Till now,the whole book is over,thanks for your support and I hope it can help you.best wish.

 
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