虚 拟 语 气
虚拟语气是一种特殊的动词形式，表示所说的话不是一个事实，而只是一种假设，愿望，建议，怀疑，猜测或不大可能实现的空想。
I.虚拟语气用在条件状语从句中
虚拟语气用在条件状语从句中，通常从句由连词if 引导。
1． 与现在事实相反的虚拟条件句
构成
条件状语从句 主句
If +主语 +动词过去式 主语+ would, should, could, might+原形动词
(be的过去式用were)
例如：
If I feared death, I wouldn’t be a communist. （刘胡兰）怕死就不做共产党员。
If there were no air, we couldn’t live. 如果没有空气，我们就不能生活。
Example:
I would ask George to lend us the money if I ______ him.
A. had known B. knew C. have known D. know
I _____ it to him if I thought he would understand.
A. shall explain B. will explain C. would explain D. explain
2． 与过去事实相反的虚拟条件句
构成
条件状语从句 主句
If + 主语 + 动词过去完成式 主语 + would, should, could, might +
have + 过去分词
例如：
If you had come a few minutes earlier, you would have met him.
如果你早来几分钟，你就会碰上他。
If there had been no air in the tube, the result of the experiment would have been more accurate.
如果试管中没有空气，实验结果就会更精确。
Example:
If you hadn’t gone with Tom to the party last night, _______.
A. you would meet John already B. you won’t have missed John
C. you will have met John D. you would have met John
3． 与将来事实相反的虚拟条件句
构成
条件状语从句 主句
If + 主语+ should +原形动词 主语 + would, should, could, might
或were + 不定式 + 原形动词
例如：
If he were to come tomorrow, things would be easier.假如他明天会来，事情就容易办了。
If the sand should be broken up, it would give out much energy.
如果沙子能被分解，它会释放出大量的能量。
注：在表示与将来事实相反的虚拟条件句中，从句中的should有时可以省略。如：
If he make the design, he might do it in some other way.
要是他来搞这个设计，他可能用另外的方法设计。
Example:
If the sea ____ to rise 50 feet, India would become an island.
A. will B. is C. was D. were
If you ____ to see Mary, what would you tell her?
A. are B. will be going C. must D. were
We might still catch the train if we ___.
A. make hurry B. haste C. make haste D. hastily
4． 错综时间的虚拟语气
在一些含有虚拟语气的句子中，如果主句与从句的谓语表示不同的时间，虚拟语气可有不同形式，即主句与从句各自按自己的时间构成虚拟形式。例如：
