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

time on it.

A. While        　    B. As      　                 C. Because　         D. If

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

A. While            　     B. As         　                      C. Because　            D. If

 ______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

   _____ 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

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