The scientist has made quite a few discoveries, of great importance to the whole world.
A. which I think they are
B. which I think are
C. I think which are
D. that I think they are
网友回答
A. which I think they are
(答案→)B. which I think are
C. I think which are
D. that I think they are
解析：此题考查非限定性定语从句。非限定性定语从句不能用关系代词that来引导，因而排除D.项；[C]项语序不对；在以Which开头的[A]、B.项中，关键要识别出插入语“I think”，这样显然[A]项中的they为多余的词，因此B.项为正确答案。