1 draining or being drained 排水; 放水.
2 system of drains 排水系统.
3 what is drained off; sewage 排出的污水; 下水道的污物.
the process or system by which water or waste liquid flows away
A handful of pebbles in the bottom of a flowerpot will help drainage.
a plan to improve the town's drainage system
1. But even the mosquito has been subdued by attention to drainage and by chemical sprays. 然而即使蚊子，也由于我们注意清理污水和喷洒化学药品就被制服了。
2. Workmen put in a proper drainage system and supplied pure drinking water. 工人安装了合适的排水装置，提供纯净的饮用水。
3. The town´s drainage is very efficient. 这城市的排水系统很好。
4. The city was even equipped with a drainage system, for a great many clay pipes were found beneath the narrow streets. 城里甚至还敷设了排水系统，因为在狭窄的街道底下发现了许许多多陶土制作的排水管道。