—Excuse me. Could you tell me____ later on?

—Wait a minute. It’s coming in ten minutes.[ ]

A. if the next train arrives.

B. if the next train will arrive

C. when the next train arrives

D. when will the next train arrive

网桥完成 【12】 间的连接，可以将两个或多个网段连接起来，网桥可以通过过滤不同网段传输的信息，避免线路的拥塞。