波河

例句：

1. 1. The river flows through the city, providing a natural boundary.
   这条河流穿过城市，提供了自然的边界。
2. 2. We need to protect the environment by reducing pollution and preserving our natural resources.
   我们需要通过减少污染和保护自然资源来保护环境。
3. 3. The river is a source of fresh water for the town.
   这条河是这个城镇的淡水来源。