语法系列复习专题-----情态动词与虚拟语气

语法系列复习专题-----情态动词与虚拟语气

 

一、一般疑问句中几个情态动词的问与答

    1.  Need I/he/…?

        Yes,you/he/…must.(不用need)

    2.  Must I/ he/…?

        No,you/ he/…needn’t/don’t(doesn’t,won’t)have to.(不用mustn’t)

    3.  May I/ he/…?

        No,you/ he/…mustn’t.(少用may not)

    4.  Could(Can)you…?

        Yes,I can (不用could)

    5.  Shall I/she/ he…?

        No,you(she,he)needn’t/can’t/mustn’t

二、情态动词表“推测”

    1.can,may,must使用的句式：

    1)肯定陈述句中：must表“肯定、必定、一定”意，may/might表“也许，或许”意。

    2)否定陈述句中：can’t/couldn’t表“不可能”意，may not/might not表“也许不、可能不”意。

    3)疑问句中：只能用can或could,不能用must,may或might。

    注意：表推测的could,might并不是指过去时间，而是表示比can,may把握性略小些的情况。

    2.对目前状态的推测：

    1)must/may/might/can/could＋be＋表语

    例如：She must be a teacher.她肯定是老师。She can’t/couldn’t be a doctor.她肯定不是医生。 He may not/might not be a doctor.他可能不是医生。

    2)must/may/might/can/could＋一些不能用于进行时的静态动词(如:have,exist,live,like,hate,own,belong to等)

    例如：She must have her own car,for she has a lot of money.

    That kind of bird may live in the valleys.

    3.对目前正在发生的事情进行推测：

    句式：must/may/might/can/could＋be doing

    例如：They must be waiting for us.他们肯定正在等我们。

    She may/might be doing her homework.她可能正在做作业。

    Can/Could he be playing football?他会正在踢足球吗？

    4.对已发生的事情进行推测：

    句式：must/may/might/can/could＋have done

    例如：There’s no lignt in the room. They must have gone to bed./She knows nothing about the film. She can’t/couldn’t have seen it./Can/Could he have been a doctor?/He may/might(not)have been a teacher./They must have been watching TV at nine last night./Can/Could she have stayed in Beijing last year?

    注意：will have done句式也可表“肯定/可能已经…”推测意。

    例如：He will have learned advanced mathematics,for he knows a lot about it. 他肯定/可能学过高等数学，因为他对此懂得很多。

三、“情态动词＋have done”用法

    1.should/ought to ＋have done,意“本应该…”，含有责备或后悔意。

    例如：You should have come here a little earlier./I ought to have sent him to school./

    2.shouldn’t/oughtn’t to＋have done,意“本不应该”，含有责备或后悔意。

    例如：You shouldn’t have watered the flower./I oughtn’t to have scolded her for such a small thing.

    3.might have done,意“过去可能做”；could have done意“本能够做”，两者都含有委婉批评或遗憾之意，也可表对过去情况的推测。

    例如：He might have gone to Nanjing with Professor Wang.last week,but he was ill.上星期他本可以和王教授一起去南京的，可他病了。We could have finished the work ahead of time.我们本来是能够提前完成工作的。

四、情态动词在反意疑问句中的用法

    1.“肯定祈使句＋附加问句”结构，附加问句常用will/would/won’t you形式。

    例如：Stand still,will/would/won’t you?

    2.“否定祈使句＋附加问句”结构，附加问句常用will/would you形式。

    例如：Don’t watch TV,will/would you?

    3.Let’s…,shall we? ; Let us…,will/won’t you?

    4.含有must句子的反意问句

    1)must表示“必须”时，附加部分常用needn’t,也可用mustn’t.例如：He must go with you,needn’t/mustn’t he?

    2)mustn’t表“一定不能”时，附加部分用may.例如：She mustn’t leave,may she?

    3)must表“一定、想必”推测意时，附加部分主要有下列几种形式：

    A.He must be an engineer,isn’t he?They must be writing now,aren’t they?(这类句子问句前部分含“must be…”或“must be doing…”。)

    B.She must have a car/live there, doesn’t she?

    C.He must have seen the film,hasn’t he？(这类句子问句前部分的谓语为must have done,句子无具体过去时间状语。)

    D.He must have seen the film last week,didn’t he?(这类句子问句前面部分的谓语为must have done,句子有具体过去时间状语。)

    E.Mother must have been shopping then,wasn’t she?(前面部分谓语为must have been doing。)

    5.含有may表推测的句子，其反意问句形式与must表推测的反意问句形式相似。

    例如：She may have finished her homework,hasn’t she?

五、几组词语辨析

    1.must与have to:must强调说话者的主观看法，have to强调客观需要，表示“不必”意要用needn’t或don’t/didn’t/won’t have to,不能用mustn’t。

    2.can/could与be able to:can多用于现在时，也可用于将来时，could只用于过去时，be able to可用于各种时态。表示“过去经过努力而做成(或没做成)”要用was/were(not) able to ，而不用could(not)。例如：He worked hard,but he wasn’t able to pass the exam.

    3.will,would,used to:都可表“习惯”意。①will表示不受时间限制的习惯性动作。如：Fish will die out of water./ She’ll sit for hours without saying anything.

②would表示过去习惯性的动作，但不涉及与现在情况的对比。如：He would walk by the river in the morning.注意：would后不能跟表状态动词。例如不能说He would be late for school last year. ③used to表示过去习惯性的动作或状态，但这种习惯现在已不存在了。如：He used to get up early. He used to be late for school.

   4.dare与need

 

六、虚拟语气在if引导的条件句的用法

1)与现在事实相反的结构：

 

2）与过去事实相反的结构：

 

3）与将来事实相反的结构：

 

**当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间来调整。例如：
    If you had worked hard, you would be very tired.
    (从句说的是过去,主句指的是现在.)
    5以上句型可以转换成下列形式:
**省略if,用“were, have, should +主语”. 例如:
Were I in school again, I would work harder.
Had you been here earlier, you would have seen him.
Should there be a meeting tomorrow, I would come.
**用介词短语代替条件状语从句：but for\without.例如:
Without air, there would be on living things.
But for your help, I couldn’t have done it.
七、虚拟语气在名词性从句中的用法
1.“wish +宾语从句”表示不能实现的愿望,汉语可译为“可惜……”. “……就好了”, “悔不该……”, “但愿……”等.
表示现在不能实现的愿望,从句的谓语动词用过去式;表示将来不能实现的愿望用“would(could) +动词原形”;表示过去不能实现的愿望时用“had +过去分词”或“(could)would +have +过去分词”.例如:
I wish it were spring all the year round.
I wish you could go with us.
We wish we had arrived there two hours earlier.
2.虚拟语气在动词一个坚持（insist）；两个命令（order，demand）;三个建议(advise,suggest,propose);四项要求（demand,require,request,ask）,等后面的宾语从句中用“(should)+动词原形”.例如:
We suggested that we (should) have a meeting.
We insisted that they (should) go with us.
The doctor ordered that she (should) stay in bed for a few days.
He demanded that we (should) start right away.
**注意:insist作“力言”, “强调”解时,宾语从句不用虚拟语气,只有当insist作 “坚持(认为)”, “坚持(应该)”解时宾语从句才用虚拟语气.例如:
  Mike insisted that he had never stolen anything.

又如suggest
3.虚拟语气用于表语从句、同位语从句
作advice, idea, order, demand, plan, proposal, suggestion, request等名词的表语从句和同位语从句,其谓语动词要用虚拟语气的结构“(should)+动词原形”.例如:
    We all agreed to his suggestion that we (should) go to Beijing for
sightseeing.
    My idea is that we (should) exercises first．
4.虚拟语气在 as if(as though)中，引导的表语从句或状语从句中的应用．
    如果从句表示的动作发生在过去，用过去完成时，指现在状况，则用过去时，指将来则用过去将来时．例如：
    He looked as if he were an artist.
    He speaks English so fluently as if he had studied English in England．
    Even if he were here，he could not solve the problem．
 5.虚拟语气用于主语从句．
    在主语从句中，谓语动词的虚拟语气结构用“ should 十动词原形”的结构，表示惊奇、不相信、惋惜、理应如此等．例如：
    It is necessary( important，natural，strange，etc) that … we should clean
the room every day.
    It was a pity ( a shame，no wonder，etc) that you should be so careless．
    It will be desired( suggested，decided，ordered，requested，proposed，etc)
that she should finish her homework this afternoon．
    在上述三种主语从句中，should意为“应该”,“竟然”，可以省去，但不可换用would.主句所用动词的时态不限．
    注意：这种从句表示的是事实．如果说话人对这种事实表现出惊奇的情感，就可用虚拟语气．反之，如果不表示惊奇等情感，that从句也可用陈述语气，例如：
    It is a strange that he did not come yesterday.
    It is a pity that you can’t swim．

八.几种常见的其他虚拟语气结构
1.虚拟语气用于定语从句
    这种从句常用在 It is( high) time( that)…句型中，定语从句的谓语动词用过去式，或 should十动词原形( should不能省略，be用 were)来表示，意为“(现在)该……”。例如：
    It is ( high) time we left (should leave).
    lt is high time we were going.
2.虚拟语气用于 if only引导的感叹句中,用法同.wish
    If only I had taken his advice.
    我要是听他的话就好了．
    If only I were a bird．我如果是一只鸟就好了．
3.虚拟语气在简单句中的应用
    l)情态动词的过去式用于现在时态时，表示说话人谦虚、客气、有礼貌或语气委婉，常出现在日常会话中，例如：
    It would be better for you not to stay up too late．
    Would you be kind enough to open the door?
    2)用于一些习惯表达法中，例如：
    Would you like a cup of tea?

I would rather not tell you.    You had better go now．    

3)用“ may 十动词原形”表示“祝愿”、“但愿”． may须置于句首，例如：May you be happy!  May you succeed!

4.would rather-----