boundary river

例句：

1. 1. The boundary riveris a critical source of water for theregion.
   边界河流是该地区的重要水源。
2. 2. Theboundary river marks the border between two countries.
   边界河流标志着两个国家之间的边界。
3. 3. Theboundary river provides habitat for many species offish and birds.
   边界河流为许多鱼类和鸟类提供了栖息地。