Had I receivd your letter,I would have written back two days ago.

问题描述:

Had I receivd your letter,I would have written back two days ago.
为什么要用Had I

一种特殊的虚拟语气表达方法.if 省略 had 提前,从而达到加强语气的目的.
又如:
Had I known you were coming today,I'd have met you at the railway station.
原句:If I had knownyou were coming today,I'd have met you at the railway station.