channel of main stream

例句：

1. 1.The river is a natural channel for fish to migrate through.
   这条河是鱼类迁徙的自然通道。
2. 2. The new technology will provide a better channel for communication between different countries.
   新技术将提供更好的不同国家之间的沟通渠道。
3. 3.The pipeline carries oil from the refinery to the storage tanks.
   这条管道将从炼油厂输送石油到储罐。