But that he came to help me ,I____ .

问题描述:

But that he came to help me ,I____ .
a) could not have succeeded b)did not succeed
c) could not succeed d)can't but succeed
请问此题考什么语法点呢?
另外我还想问:
But that he came to help me ,I could not have succeeded .是不是可以改写成:
If it were not that he came to help me ,I could not have succeeded .

考察完成时,虚拟语气
没有他来帮助我,我是不会成功的.(现在已经成功)选A
could have done 是“本可以做某事(而实际上没做)”,这里加上not就是我本来是不会成功的(现在已经成功),是虚拟语气的用法.
个人意见