Underclay
n. (煤层下的)底黏土层
🗣️ 情景例句
He's always in and out of jobs.
他老是跳槽。
My favorite game when I was a child was making snow angels in the freshly fallen snow.
我在孩提时代最喜欢玩的游戏，是在刚下的雪上堆雪天使。
Not at all, dear. It was a pleasure.
不必客气，亲爱的。这样我很高兴。