channel span

例句：

1. 1. The radio station is broadcasting on channel 25.
   这个电台正在频道25上广播。
2. 2.She used to travel by boat across the channel.
   她过去经常通过船只横渡海峡。
3. 3.The ship's captain decided to use a different channel for communication.
   船长决定使用不同的频道进行通信。