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                                               D. I think which is 答案：【解析】选A。考查非限制性定语从句及插入语。此处I think为插入语，which是引导定语从句的关系代词。

查看本题答案和解析