It was quite a serious accident, _________ caused by careless driving.
A. which I think was B. I think which was
C. which I think it was D. I think which it was
It was quite a serious accident, _________ caused by careless driving.
A. which I think was B. I think which was
C. which I think it was D. I think which it was
A
本题考查由which引导的非限制性定语从句，which替代先行词accident 在定语从句中作主语。I think 是插入语，放在which后面。