Had I receivd your letter,I would have written back two days ago.为什么要用Had I
网友回答
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 ing today,I'd have met you at the railway station.
原句:If I had knownyou were ing today,I'd have met you at the railway station.
======以下答案可供参考======
供参考答案1:
虚拟语气翻译：如果我收到你的信，2年前我就会给你回信了
供参考答案2:
虚拟语气had提前，本来应该是if I had received
had提前加重点语气
供参考答案3:
过去完成时疑问句啊