sewage system

例句：

1. 1. Thecity has invested heavily in improving its sewage treatment facilities.
   该城市在改善其污水处理设施方面投入了大量资金。
2. 2. The sewagesystem is responsible for treating the wastewaterfrom the city's streets and alleys.
   污水系统负责处理城市街道和小巷的废水。
3. 3. The sewage system needsregular maintenance to prevent contamination ofthe waterways.
   污水系统需要定期维护，以防止水道受到污染。