2015考研英语重点语法总结之虚拟语气

很多同学一提起考研英语备考就拿起词汇书，立马变身“抄写哥”开始狂背单词，仿佛考研英语的复习就只有背单词这一件事情。 但在实际的考试中，又有很多同学发现：在一个长难句中，也许整个句子中所有的单词考生都认识，但仍看不懂整个句子的意思。这其中原因主要是考生并没有深刻的感受到英语语言的特点。英语它是有血有肉有骨骼的。单词和短语只能说是英语的血肉，而英语的语法则是它的骨骼，要想吃透考研英语，考研英语语法是不可或缺的。

考研英语大纲中对要求考生掌握的语法知识有明确的要求。其中有几个较大同时也较难的语法项目值得考生特别注意，因为这些语法知识一般也是命题人比较喜欢的。现在，小编就给大家总结一下这些常考的且难度相对较高的语法项目，以便帮助考生容易且有条理的掌握这些语法顽疾。

今天我们首先为大家梳理一下“虚拟语气”方面的内容。

虚拟语气的考点分为以下4类：

（一） if 引导的从句类

由if 引导的条件句有两种形式，一种是真实条件句，例如：If you ask him, you will get a satisfactory answer. 另一种形式是非真实条件句，通过虚拟语气来表达，例如：If I were you, I would pursue the research and carry on the experiment until I get a result. 在这句话中，说话者假设“我是你”，但是真实情况并非如此，所以使用虚拟语气。

（1）相反的非真实条件句，从句中用一般过去时，主句中用would/could/should加动词原形，be 动词的过去形式为were。

If I were the president, I would declare November 1 a national holiday.

（2）与过去事实相反的非真实条件句，从句中用过去完成时态，主句中用would/could/should+have done。

If the passenger had got to the airport ten minutes before the departure time, he wouldn't have misses the flight.

（3）与将来事实相反的非真实条件句，从句中用should do或were to do 结构，主句中用would/could/should加动词原形。

He is such a chain smoker. If he were to give up smoking tomorrow, I would walk on my head.

（4）混合时态的虚拟，指的是主句和从句分别表示两个时态，动词形式依照上述三种形式相应变化。

If he had put all the important files in the safe yesterday, his boss wouldn't be scolding him so angrily now.

（5）该类虚拟语气经常省略if, 将从句中的系动词或助动词提到主语之前，变成倒装句，考生对这种形式应该理解和掌握。

The millions of calculations involved, had they been done by hand, would have lost all practical value by the time they were finished.

（6） 表示虚拟含义的条件并不一定都使用条件句来表达，还可以通过其他形式来表示，例如with, without , under…condition, but for等，考生应该注意。

But for the development of modern science and technology, man couldn't have walked on the moon.

（二） 从句中的（should）do 句型类

（1）英语中有些表示要求、建议、提议、命令、意愿等的形容词、动词和名词，其后若跟随有主语从句、宾语从句、表语从句或同位语从句，从句中的动词要求用虚拟语气形式，即动词原形或should+动词原形。

属于该类的常见形容词：advisable, appropriate, desirable, essential, imperative, important, insistent, keen, necessary, preferable, urgent, vital等。

属于该类的常见动词有：advise, ask, beg, decide, demand, desire, determine, insist, intend, maintain, move, propose, order, recommend, request, require, resolve, suggest urge等。

属于该类的常见名词有：advice, decision, demand, desire, insistence, instruction, order, motion, preference, proposal, recommendation, request, requirement, resolution suggestion等。

例句：The board deemed it urgent that these files should be printed right away.

（2）由lest, for fear that, in case引起的从句也多用 “should+动词原形”的形式表示虚拟语气。

例如：I had to restrain him lest he should give us away.

（三） 特殊句型类

以下所列单词或短语后所引出的从句，如果是现在的情况，要用一般过去式；如果是过去的情况，要用过去完成体。

（1） It is about/high time（that） “是……的时间了”。此句型要表达的含义是“早该”，言外之意就是目前还没有发生，所以用虚拟语气。

It is high time that the government took some measures to protect the environment.

（2） would rather/had rather “宁愿……”

I could go myself but I would rather you went.

（3） wish “希望……”

I wish I were as rich as you!

（4） If only “要是 ……就好了”

由if only 引导的句子经常被用来表示不可能或很难实现的愿望，动词过去式，be 动词用were。也可以用来表示对过去已经发生的事情表示遗憾，动词用过去完成式，其作用相当于I wish引导的句子。

例如：If only he weren't so thick-skinned.

If only you would listen to reason.

If only you hadn't told him what I said.

（5） as if/as though “仿佛，好像”

可以用来陈述事实，也可以用来表示假设，（好像是什么而实际上或心里认为根本不是那回事）。表示假设的句子中，动词用过去式表示现在，用过去完成式表示过去。

例如：Sometimes he acts as if he didn't have a brain in his head.

注意：as if引导的从句也可以用于真实语气。

（四） 单用句型类

（1） should have done 本该做却没做

（2） should not have done 本不该做却做了

（3） needn't have done 本没有必要做却做了

（此类句型还包括由其他助动词would, could 等加上have done 的结构。）

例句：We should have told them the truth from the beginning.

He shouldn't have blamed his son for breaking the glass.

I needn't have taken my umbrella, since the hotel prepared many for guests.