key river basins的用法和樣例：
例句
- National standards would have stricter limits for discharge of pollutants in key river valleys.
提高重點(diǎn)流域水污染物的國家排放標準。 - Pollution control in key river valleys and regions was strengthened,and the environmental quality improved in some cities.
重點(diǎn)流域和區域污染防治得到加強，部分城市環(huán)境質(zhì)量有所改善。
