I was lucky to have missed the early bus this morning,otherwise I[ ]have been involved in a terrible accident .C must D

问题描述:

I was lucky to have missed the early bus this morning,otherwise I[ ]have been involved in a terrible accident .C must D would

must是一个太绝对了.
从语境中就能判断出来,如果不是这个错过这个车,就一定卷入其中.
would这个词是虚拟语气,毕竟是在假设呢.
从虚拟语气考虑,更好!