The professor has written another book of great importance to puter science.
A. which I think it is
B. and I think is
C. which I think is
D. when I think is
网友回答
A. which I think it is
B. and I think is
(答案→)C. which I think is
D. when I think is
解析：
I think是插入语。A答案中的it是多余的。