Underdrainage
n. 暗渠排水, 地下排水
??? 情景例句
Where did you get such a nice tan?
你到哪把皮膚曬成棕色的？
Pleased to meet you.
認識你很高興。
when a significant number of people are living permanently in space.
如果有相當數量的人永久性地住在太空，