HadIifknownit,I'ddoneitmyself不省略的假设句是什么就是这道题：,I'dhavedoneitmyself.A.IfIwouldhaveknownit.B.IfIhadhaveknownit.C.HadIknownit.正确答案是C.但我觉得B也可以,意思是如果我已经

Question

Had I if known it,I'd done it myself不省略的假设句是什么
就是这道题：
______,I'd have done it myself.
A.If I would have known it.
B.If I had have known it.
C.Had I known it.
正确答案是C.但我觉得B也可以,意思是如果我已经知道是这样……
请问B为什么不对?

Answer 1

此题考察虚拟语气.根据语境翻译看,应该是对过去事实虚拟.构成如下：
If 从句（ had done ) + 主句（ should / would /could /might + have done )
具体到你的句子来说,若用完整的if 从句表达,应是：If I had known it
仅供参考.