back-water at pier

例句：

1. 1. The back-water at the pier is a breeding ground for mosquitoes.
   码头上的污水是蚊子的滋生地。
2. 2.The sewage from the city flows into the back-water at the pier.
   城市的污水流入了码头上的污水。
3. 3.The workers are cleaning up the back-water at the pier to prevent pollution.
   工人们正在清理码头上的污水，以防止污染。