混合条件句表示主句与从句的动作发生在不同的时间，这时主、从句谓语动词的虚拟语气形式因时间不同而不同，这叫做混合条件句。

例句：

If you had asked him yesterday, you would know what to do now.

（从句与过去事实相反，主句与现在事实相反。）

If it had rained last night （过去）, it would be very cold today （现在）.