例如:
If he had come yesterday,he would have know it.
=Had he come yesterday,he would have known it.
例如:
If I were there,I would help them.
=Were I there,I would help them.
例如:
If I should have 2000,000 yuan,I would buy a good car.
=Should I have 2000,000 yuan,I would buy a good car.
虚拟语气主要用来表示假设,而非客观存在的事实,所陈述的是一个条件,不一定是事实,甚至完全与事实相反。虚拟语气通过谓语动词的特殊形式来表示。此外如需表达主观愿望或某种强烈的感情时,也可用虚拟语气。