He has made another wonderful discovery,___ of great importance to science.
A. who I think it B.which I think it is C. that I think is D. which I think is
He has made another wonderful discovery,___ of great importance to science.
A. who I think it B.which I think it is C. that I think is D. which I think is
D
首先去掉插入语I think，使选项明朗化；因前后都是两个无连词的句子，可判断后句为非限制性定语从句。