Protocalcium
原钙, 初钙
🗣️ 情景例句
A rolling stone gathers no moss.
滚石不生苔，转业不聚财。
Do not speak of your happiness to one less fortunate than yourself.
不要向不如你幸运的人述说你的幸福。
I must always keep on trying to do my best.
我必须始终继续作出最大的努力。