问题
选择题
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
答案
答案：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。