Calculuses
微积分, 微积分学, 计算, 演算, 结石, 积石, 牙垢
🗣️ 情景例句
kick off your shoes, and sit down.
脱掉你的鞋子， 坐下来。
The fire is the test of gold;adversity of strong man.
烈火试真金，困苦炼壮士。
It's a pencil-box.
一只铅笔盒