Underdrain
n. 阴沟, 地下沟道, 盲沟, 暗渠
🗣️ 情景例句
Here they are. Family Album, U.S.A.
就在这里。美国写真！
Thank you for your kind cooperation.
谢谢您的合作。
Gradually the river grows wider, the banks recede,
然后河面渐渐地变宽，两岸后撤，