虚拟语气用法归纳
英语的动词一般可带有三种不同的语气：陈述语气，祈使语气和虚拟语气。不同的语气用动词的不同形式（有的还借助句法形式）来表示。
一、 虚拟条件句
条件句有两类：一类是真实条件句，一类是虚拟条件句
如果假设的情况是有可能发生的，就是真实条件句，谓语用陈述语气。 If you don’t work hard, you will fail.
If it is fine tomorrow, we will go for a picnic.
如果假设的情况过去、现在、将来都不存在，则为虚拟语气 虚拟条件句和对应主句的动词形式列表：
条件从句的谓语动词形式主句谓语动词形式
与过去事实相反的假设had donewould/could/might/should have done
与现在事实相反的假设过去时(was→were)would/could/might/should do
与将来事实相反的假设过去时 (was→were )
should do; were to dowould/could/might/should do
1.与现在事实相反的虚拟
What would you do if you won the lottery?
If I were you, I would seize the chance to go abroad.
If I had a lot of money now, I would travel around the world. 2.与过去事实相反的虚拟
If you had been here yesterday, you would have seen her.
If he had driven more carefully, he would not have had the car accident yesterday. 3. 与将来事实相反的虚拟
If it were to rain/should rain/rained tomorrow, our plan would be put off. If we were to picnic, we would not be able to help.
二、错综、混合虚拟语气
通常，在上面表格里反映的是非真实条件句的虚拟语气模式，从句和主句的谓语动词时间是一致的，如果两者时间不一致，此时就是混合型虚拟语气。混合型虚拟语气的使用要求“各自为政”，即从句和主句根据各自假设的时间不同，采用上面表格中对应的的谓语动词形式。
1. If I had seen you, I would not be so worried now. (从句是对过去的假设，主句是对现在的假设)