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虚拟语气``请详细说明 虚拟语气`的主从句时态``

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虚拟语气``
请详细说明 虚拟语气`的主从句时态``
虚拟语气
有些条件句是可能实现的,称为真实条件句. 虚拟语气是动词的一种特殊形式,用来表达说话人的意愿.请求,设想,等未能或不可能实现的事实,或说话人看来实现可能性很小的情况.做这类题时首先要弄清楚虚拟语气的各种句型,即由if引导的虚拟条件句,省略if的倒装形式,可跟虚拟语气的宾语从句,同位语从句,表语从句的句型,以及表示祝愿或感叹的句子和由without, but for等介词引导的短语或句子.
四级对虚拟语气的测试主要涉及以下方面:
1). 主语从句,同位语从句中虚拟语气的用法.
2). 宾语从句中虚拟语气的用法,尤其是wish 虚拟语气结构的用法.
3). If条件句中虚拟语气的用法,应特别注意省略if的倒装结构是考试的重点.
4). would rather 等结构中虚拟语气的用法.
5). if only结构中虚拟语气的用法.
6). But, or, otherwise 等含蓄条件句的用法.
7). It’s time (that) 等结构中虚拟语气的用法.
1. 虚拟语气在虚拟条件句中的运用
(1)虚拟语气现在时. 用以表示与现在事实相反的假设或现在实现可能性不大的情况.

条件从句
主句

动词过去式(be多用were)
Would/should/could/might + 动词原形


Eg. If I were a bird, I would fly to you.
If it were not for their help, we should be in a very difficult position.

(2) 虚拟语气过去式. 表示与过去事实完全相反的假设.

条件从句
主句

had + 过去分词
would/should/could/might + have +过去分词


Eg. If we had started earlier, we should not have missed the train.
If she hadn’t been ill, she might have come.

(3)虚拟语气将来式. 表与将来情形相反的假设或极少有可能实现的情况.
条件从句
主句

动词过去式或should +动词原形或were to +动词原形
would/should/could/might +动词原形


Eg. If Professor Li should have time tomorrow, we could ask him some questions.
If there should be no air, there would be no living things.

◆ 书面语中,上述(1),(2),(3)三种时态的虚拟句中,如果从句里含有should, had, were或其他助动词,则可将从属连词if省去,将助动词.情态动词.be或have放在句首形成部分倒装.
Eg. Were he in your position, he’d have done the same.
Had I had time, I would have done that yesterday.
Should he come tomorrow, I should give him the dictionary.
(1) 错综时间虚拟句
通常情况下,在非真实条件句中主句和从句的谓语动词所指时间是一致的, 但有时也可能指不同的时间,这时要根据上下文的意思采用不同的谓语动词形式. P 116, 2
Eg. If I were you, I would have taken his advice. (从句指现在, 主句指过去)
If I had taken my raincoat with me this morning, I would not be wet now. (从句指过去,主句指现在).

(2) 含蓄条件句
有时假设的情况并不以条件从句表示出来,二是暗含在上下文中,比如通过介词短语来表示.
Eg. But for your advice, I could not have done it so successfully.
The change could not have taken place without the open-door policy.
I was so busy then, Otherwise, I would have told him the answer.

(3) 虚拟语气在某些从句中的应用.
A) 在wish, suggest, order, demand, propose, command, request, recommend, require, decide, insist, desire, urge等动词的宾语从句以及would rather /sooner 后要用 “ (should) +动词原形” 来表示愿望,建议, 命令,要求等; 由上述动词派生或转化的名词suggestion, proposal, plan, motion, recommendation, demand, order, desire, request, requirement, insistence, advice, decision , obligatory 义不容辞的, 必须的 等的同位语从句或表语从句中也要用相应的虚拟形式.
Eg.
B) 在It is/was + 某些形容词 + that 从句的句型中,that从句中的谓语动词常用虚拟语气,即 “should + 动词原形”
这些形容词有:
important, necessary, essential, imperative, natural, strange, advisable, desirable, possible, probable, astonishing, surprising, desired, suggested, requested, recommended, ordered, proposed, decided, moved等.
“ should + 动词原形(或完成形式)” 可表示惊奇,遗憾,怀疑,不满等.
ⅰ. 用于expect, believe, think, suspect 等动词的否定或疑问形式后的宾语从句中.
Eg. I never expected that the new apartment should be so small.
ⅱ. 用于 “It is a pity, it is a shame, it is no wonder 等 + that” 等结构后的主语从句中.
Eg. It is a pity that he should be so careless.
C) 在由for fear that, in case, lest 等引导的状语从句中,用 “ should + 动词原形” 表示 “惟恐”的意思.
Eg. He handled the instrument with care for fear that it should be damaged.
D) 在 “ It is (about/ high ) time + that (从句)” 中,谓语动词常用过去式表表示虚拟语气.
Eg. It is high time that people learnt English.
E) 在 “as if/ as though” 引导的状语从句中,谓语动词与wish的宾语从句的虚拟形式相同.
Eg. He works with such enthusiasm as if he never knew fatigue.
He speaks English as though he were an American.
F) 在 look, seem等动词后的 “as if / as though”从句中,当表示真实情况时,用陈述语气; 否则,用虚拟语气.
Eg. It seems as if they know each other. (真实情况)
It seems as though it were already spring. (虚拟语气)
G) 用在if only 引起的感叹句中.
Eg. If only the driver didn’t drive so fast!