Underclay
n. (煤层下的)底黏土层
🗣️ 情景例句
How do I do that?
我该办什么手续呢？
Would it be too much to ask you to respond to my question by tomorrow?
可以请你在明天以前回复吗？
They had just had enough time to swim out of danger when the boat again completed a circle.
他们刚刚来得及游出危险区，快艇就又转完了一圈。