____for your help,we wouldn't have succeeded.

问题描述:

____for your help,we wouldn't have succeeded.
A,Hadn't it been B,Had it not been C,If it had been D,If it were
但是A和B的区别在哪儿?

我来试试:
A = Hadn't it been = Had not it been,不符合虚拟语气的倒装句结构.
B = Had it not been (虚拟语气的倒装句=If it had not been)