A drain carries surplus water to the river.

【carry】一根排水管把多余的水输送到河里去。

These systems remove surplus water during periods of increased rainfall. However, both legal and illegal building projects have blocked the flow of water.

这些系统在雨水增多的时候用来转移过剩的雨水。然而，一些合法和非法的建筑项目堵塞了水流。