You look as if you____a ghost.A had seen B have seen C were to see D could see

问题描述:

You look as if you____a ghost.A had seen B have seen C were to see D could see
为什么选A呢。

A.had seen
虚拟语气为什么选A呢。我不明白耶,虚拟语气与过去事实相反的用过去完成时