help!I __ with you because I was in London at the time.

问题描述:

help!I __ with you because I was in London at the time.
A couldn't go B couldn't have gone C shouldn't have gone D needn't have gone

A,我觉得couldn't go 代表的是虚拟,.和一般过去时相对应.整句话"我不能跟你走,因为我那时在伦敦"说明"go with you"是在"was in London" 之后的动作.