虚拟语气只用would不用had?

问题描述:

虚拟语气只用would不用had?

两者都用,但用法不一样.比如,
Had I known about it, I would have gone to the meeting last night.
过去虚拟语气,意思是:如果我知道的话,我会出席昨晚的会议.
希望对你有所帮助.