【题目】 He made another wonderful discovery, _____ of great importance to science．
A. which I think is B. which I think it is
C. which I think it D. I think is
在线课程【答案】A
【解析】
试题分析：考查插入语：句意：他做出了一个重大发现，我认为这对科学是非常重要的，which引导的是非限制性定语从句，I think是插入语，在which后面，去掉I think可知which是定语从句的主语，it是多余的，选A 。