Question

He made another wonderful discovery, ______ of great importance to science.

A．which I think it is	B．which I think is
C．which I think	D．I think which is

Answer 1

B

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B。
点评：插入语用法归纳 插入语用法很多,在句子中的位置比较灵活,在学习中应当认真去体会。插入语可以是用简短的句子结构作插入语。这类短语有:I think, I hope, I guess, I believe, I suppose, I wonder, I tell you, I say, I'm afraid, I'm sure, you see, you know, as you know, that is, that is to say, what's more等等,它们可以置于句中或句尾。