1. 落水管：downpour 暴雨 | downspout 落水管 | downstand beam 肋形楼板梁
2. 降液管：downshot burner 下射喷燃器 | downspout 降液管 | downstream tube 下游管
3. 水落管：downspout 水落管 | downstage 前台的 | downstair 楼下的
4. 下导管：doubleweighingmethod 双重秤量法 | downdraft 向下通风 | downspout 下导管
1. (把雨水从屋顶输送到下水道的)雨水管，排水管
A downspout is a pipe attached to the side of a building, through which water flows from the roof into a drain.
e.g. He installed rain gutters and downspouts.
他安装了雨水檐沟和排水管。