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

______ the Internet is of great help, I don’t think it’s a good idea to spend too much time on it.
A. IfB. WhileC. BecauseD. As
本题选择B,但是我不太明白D为什么不可以?感谢您的回答!
如果选择as引导让步状语从句，表达“尽管”的含义，这句话也说的通呀，为什么不可以呢？