_____ the Internet brings much profit in, it can cause o lot of social problem.
A. If B. While C. Once D. When
_____ the Internet brings much profit in, it can cause o lot of social problem.
A. If B. While C. Once D. When
B
考查连词的辨析。依据句意来突破。从profit和problem发现前后对比转折，故选B