虚拟语气表示现在、过去、将来情况的虚拟条件句。编辑老师整理的这篇大学英语四级语法讲解介绍了使用虚拟语气的条件及虚拟语气中常见的谓语动词，我们一起来看一下吧!
1. 表示现在/过去/将来情况的虚拟条件句 虚拟条件句主要有三种结构：
1) 表示与现在情况相反：主句谓语用“would / could / might +动词原形”，从句谓语用“动词的一般过去时”(动词be的过去式一律用were)。
If I were you, I would not accept his offer.
If I had time, I would certainly go to the cinema with you.
2) 表示与过去情况相反：主句谓语用“would / could / might + have +过去分词”，从句谓语用过去完成时。
If I had got up a little earlier, I wouldn’t have missed the train.
If I had been more careful, I might have passed that exam.
3) 表示与将来情况相反：主句谓语用“would / could / might +动词原形”，从句谓语用“were +动词不定式”或“should +动词原形”。
If I were to do the job, I would not be able to have enough time to study.
If it should rain tomorrow, I would not go out with you.