关于英语虚拟语气的一些问题._____you were coming today ,I'd have met you a

关于英语虚拟语气的一些问题.
_____you were coming today ,I'd have met you at the railway station.
A.Have I Known B.I have known
C.I had known D.Had I known
我选的是C 按照虚拟语气的语法 表示过去式情况 从句If+had+过去分词、主句have+过去分词.
想问A和D的情况可能出现么,会有倒装的这种把HAD提前的形式吗?
________what was going to happen , i would never have left her alone.
A.had i known B.if i knew
C.If i know D.if had i known
我选的是B,对吗,请解释理由.
If you _____（buy）her the gift yesterday .she ______(not be)so angry now.
我填的是.have bought / wouldn't be
从句式过去式,主句是现在式,请问是这样填写么?
以上 谢谢.