_______ the Internet is of great help, I don't think it's a good idea to spend too much time on it.

A.If

B.While

C.Because

D.As

答案及解析： B

解析：考查连词。此处意思是“尽管网络很有帮助，……”，选项中能表示让步的只有while，相当于although。其他选项都不能表示让步的意思。