Lapis dentalis
[医] 牙垢, 牙石
🧩 词语组成解析
[医] 石
🗣️ 情景例句
You graduated from engineering school.
你是从工学院毕业的。
Math major
专攻数学
We enjoy staring at them, entranced as they go about their business, unaware (we hope) of our presence.
我们喜欢入迷地看它们做事，它们不知道（但愿如此）我们就在它们身边。