高中英语情态动词及虚拟语气的复习

情态动词

情态动词没有人称和数的变化,后面直接跟动词原形.

助动词有: have, has, had, do, does, did, done, shall, should, will, would

情态动词主要有:can, could, may, might, must, have to, had better, need, dare, shall, should, will, would, ought to

各情态动词的用法:

Can, could,be able to

1.       表能力.此时can 可以与be able to互换, 但当叙述过去经过一番努力成功做到了某事,不可用could,只能用 was(were) able to

Eg: He could (was able to) swim when he was six years old.

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

2. 表可能,能够

I’m sorry. I can’t do that. 对不起,我不能做那事.

3. 表允许,许可. 此时,(can=may, can’t=must not,  could=might); could还可提出委婉的请求.

4.表推测, 常用于否定和疑问句.这种情况下, can, could没有时态上的区别,只表示可能性的大小,can 比could可能性大.

 

May,might的用法

1. 表请求许可(否定为must not)

2. 表没有把握的推测(一般用于肯定句中)

3.may放在句首表祝愿

4. may/might 构成的短语

May/might as well+动词原形,意为”不妨”

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

may well+ 动词原形  表”理所当然”

Eg: You may well say so. 你有足够的理由这样说.

may as well + 动词原形 + as +动词原形  与其…..不如…..

Eg: You might as well throw your money away as lend it to him.

 

must, have to

1.       两词都有”必须”的意思, have to 表客观的需要, must 表主观要求.

My brother was very ill, so I have to call the doctor in the middle of the night.

He said they must work hard.(表主观要求)

have to 有人称, 数和时态的变化, 而must只有一种形式.

否定结构中: don’t have 表”不必” ; must not表”禁止”

2.       表肯定的推测

 

will, would的用法

would like to do sth= want to do sth 想要做某事

Will you …? Would you …? 表肯定含义的劝说,疑问句中一般用some,而不用any. Eg: Would you like to have some cake?

 

,ought to 和should的用法

1.       ought to: 应该, 表道义上的责任

should: 应该, 从说话人的角度来看,某人应该做某事.

eg: You are her mother you ought to look after her.

We should encourage him for we are his classmates.

 

need 和dare的用法

1.       两词都既可做情态动词又可做实义动词.作情态动词时,两者都只用于疑问句,否定句和条件句; 作实义动词时need后接动词需加to, 而dare作实义动词时后面可直接跟动词原形.

2.       need doing sth 表被动含义, 相当于need to be done.(此时为实义动词)

同样的requir, worth后面接doing也可表示被动.

The room needs cleaning. = The room needs to be cleaned.

 

情态动词表推测的用法:

can,could, may, might, must都可表示推测,用法如下:

1): 情态动词+动词原形:   表示对现在或将来情况的推测.

I don’t know where she is. She may be in Wuhan.

2): 情态动词+动词现在进行时: 表现在或将来正在进行的动作的推测.

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

3): 情态动词+动词完成时, 表示对过去情况的推测.

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

4): 推测的否定形式和疑问形式用”can’t, couldn’t”

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

 

need have done, 需要做某事而没做 needn’t have done 本没必要做某事

ought to have done, should have done 本应该做某事而没做

He ought to (should) have been more careful in this exam.

 

 

Practice

1)      Sorry I’m late. I ＿＿＿＿＿ have turned off the alarm clock and gone back to sleep again.

A. might B. should C. can D. will

2)      My sister met him at the Grand Theater yesterday afternoon, so he ＿＿＿＿＿ your lecture.

A. couldn’t have attended B. needn’t have attended

C. mustn’t have attended D. shouldn’t have attended

3)      Jack ＿＿＿＿ yet, otherwise he would have telephoned me.

A. mustn’t have arrived B. shouldn’t have arrived C. can’t have arrived D. need not have arrived

4)      I was really anxious about you. You ＿＿＿＿＿ home without a word.

A. mustn’t leave B. shouldn’t have left C. couldn’t have left D. needn’t leave

5)      I told Sally how to get here, but perhaps I ＿＿＿＿＿ for her.

A. had to write it out B. must have written it out C. should have written it out D. ought to write it out

6)      —Is John coming by train﹖ —He should, but he ＿＿＿＿＿＿ not. He likes driving his car.

A must B. can C. need D. may

7)      —I hear you’ve got a set of valuable Australian coins. ＿＿＿＿＿＿ I have a look﹖ —Yes, certainly.

8)      A. Do B. May C. Shall D. Should

9)      Mr Bush is on time for everything. How ＿＿＿＿ it be that he was late for the opening ceremony﹖

A. can B. should C. may D. must must be

10)   —Are you coming to Jeff’s party﹖ —I’m not sure. I ＿＿＿＿ go to the concert instead.

A. must B. would C. should D. might

11)   I should have been there, but I ＿＿＿＿＿ not find the time.

A. would B. could C. might D. should

12)   Johnny, you ＿＿＿＿ play with the knife, you ＿＿＿＿ hurt yourself.

A. won’t; can’t B. mustn’t; may C. shouldn’t; must D. can’t; shouldn’t mustn’t

13)   —Will you stay for lunch﹖ —Sorry, ＿＿＿＿. My brother is coming to see me.

 A. I mustn’t B. I can’t C. I needn’t D. I won’t

14)   —Could I borrow your dictionary﹖ —Yes, of course you ＿＿＿＿。

A. might B. will C. can D. should

15)   —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. need

16)   The old man is always hunting the lions, so terrible things ＿＿＿＿＿ happen to him.

 A. might B. would C. should D. could

17)    The fire spread through the hotel very quickly but everyone ＿＿＿＿ get out.

 A. had to B. would C. could D. was able to

18)   —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

虚拟语气;

英语的动词一般可带有三种语气;陈述语气, 祈使语气, 虚拟语气.不同的语气用不同的动词形式来表示.

虚拟语气的基本作用是：

1. 表达假设的情况，与事实相反；

2. 表达异想天开很难实现的愿望；

3. 表达建议、命令、劝告等语气。

常用于if条件状语从句,主语从句,表语从句,宾语从句.

A. 虚拟语气在if条件状语从句中的用法

1): 与现在事实相反:

If + 主语 +动词过去式, 主语 +should/would/could/might+动词原形

Eg; If there were no air, people would die.

2): 与过去事实相反:

If + 主语+had+动词过去分词, 主语+ should/would/could/might+have +过去分词

Eg: If you had got up earlier, you would have caught the bus.

3): 与将来事实相反(假设将来的情况)

If + 主语+ should/were to/过去式+动词原形, 主语+should/would/could/might+动词原形

Eg: If it were Sunday tomorrow, we wouldn’t have an exam.

If you were to visit the school tomorrow, you would see me.

4) 含蓄条件句中, 虚拟语气的用法.(含蓄条件句指不用条件从句, 用其他形式来表示假设情况的从句.)

用with,without等介词短语或分词短语或者独立主格结构来替代条件从句.

We might have failed without your help.

= We could might have failed if you hadn’t helped us.

Having know that in time, we could have stopped it.

= If we had known that in time, we could have stopped it.

用相当于if的其他连词表示虚拟结构:

Otherwise,否则,不然… ;   in case, 假如;    but that, 要不是;

on condition that,条件是…;   unless, 除非;   suppose/ supposing (that)假如…;

So long as,只要…;    provided/providing (that)如果…;

虚拟条件句中的倒装:

在非真实条件句中,有were, had, should, would等词时,可以省略if,将were, had, should, would放到主语前面,构成倒装.

Eg: If I should meet her, I would tell her.

=Should I meet her, I would tell her. (省略,倒装)

 

B. 虚拟语气在宾语从句中的用法:

在suggest, insist, order, demand, request, command, propose, desire等表建议,命令或要求等动词后的宾语从句要用虚拟语气.

注: suggest 作”建议”解时, 其后所跟宾语从句要用虚拟语气.

           作”暗示, 表明”解时,从句不用虚拟语气.

His face suggested that he was angry.

Insist作”坚持说”解时,不用虚拟语气

   作”坚决要求,硬要..”解时,用虚拟语气.

He insisted that he was innocent.他坚持说他是无辜的.

 

C. 其他特殊结构中的虚拟语气

1)  wish后的宾语从句中要用虚拟语气，而在虚拟语气中时态的应用类似在非真实条件中从句时态的应用。

表示现在或将来的愿望用：主语＋wish ＋从句(主语＋过去时)；表示一个过去没有实现的愿望用：主语＋wish +从句(主语＋过去完成时)；

　　例(1)I didn’t go to the party, but I do wish I had been there.

2)  if only +句子(过去时/过去完成时)“要是…就好了”

　If only 后面的句子如果是对现在或将来情况的虚拟，用过去时did ；如果是对过去情况的虚拟，用过去完成时had done . 要注意与if 区别，if 只表示假设，“如果”，用真实语气；而if only 表示不可能实现的情况，用虚拟语气。

　　例如：If only the alarm clock had rung. 当时闹钟响就好了。(对过去虚拟)

　　If only I were rich. 要是我富有就好了。(对现在虚拟)

3)  would rather＋句子(过去时)

　　表示宁愿、宁可的意愿，语气比较婉转。后接过去式。

　　例(1)I am too busy these days. I would rather all of you came next month for a dinner.

　　例(2)I’d  rather you didn’t touch that, if you don’t mind.

4)　 it is time(that)，it is high time (that)…句型中，谓语动词用过去时，表示早该做而未做的事，意思是该……了、早该……了.

　　例(1)Let's finish our homework in a few seconds; it's time we played football.

　　　　　例(2)Don’t you think it is time you gave up smoking?

　

5)　　以as if，as though引导的从句

　　在as if，as though引导的从句中，如果谈论的是不可能或不真实的情况时，它们所引用的状语从句要用虚拟语气，动词形式和wish后面的从句动词形式变化相同。

　　例：He talks as if he knew everything in the world.

 

D,  should+动词原形及should的省略

　　(1)、一些表示建议、要求、命令等的动词本身隐含说话者主观的意见。因此这些动词(或其变形，如名词，形容词，分词等)后面的从句应使用虚拟语气，即“should do”结构，其中的“should”常被省略。如：

　　表“提议、建议”的动词：suggest ,advise, propose, recommend, move(提议);

　　表“要求、主张”的动词：insist, require, request, demand , desire ;

　　表“命令”的动词：order, command.

　　例(1)I don’t think it advisable that Tom be assigned to the job since he has no experience.

　　例(2)His mother insisted that he put on the coat when going out.　　(省略了should)

　　例(3)The doctor advised that Mr. Malan have an operation right away so as to save his life.　　(省略了should).

　　(2)、It is necessary/important/essential/ vital/urgent / surprising/ amazing that引导的主语从句中，从句的谓语动词要用should+原形动词，should也可以省略。此类形容词的特点是表示重要性或吃惊。

　　例(1)it is vital that enough money be collected to get the project started. 　　

　　例(2)It’s urgent that a meeting be arranged before the final decision is made.

　(3)、以in case, lest, for fear that引起的状语从句，表示“以防，以免”。其形式为should+动词原形。如：

　　He took his raincoat with him in case it should rain.

　　他把雨衣带在身上以防下雨。