The Internet is a wonderful discovery of great significance to people’s lives.A. as is I

问题补充：

The Internet is a wonderful discovery, of great significance to people’s lives.

A. as is I think.

B. which think it is

C. which I think is

D. as I think

答案：

A. as is I think.

B. which think it is

(答案→)C. which I think is

D. as I think

解析：考查定语从句，根据句子结构可知，该句为定于从句，先行词是前面一个句子，在从句中作is的主语，I think是插入语，

句意为，英特网是一个伟大的发明，它对人们的生活非常重要。