Predentin
前期牙(本)质, 原牙质
🗣️ 情景例句
I have no spare time for hobbies or activities.
我没有时间去爱好什么。
Learning makes a good man better and ill man worse.
知识能使好人更好，坏人更坏。
All the other boys are Chinese. All of the Chinese students are Young Pioneers.
其余的男孩都是中国人。所有的中国学生都是少先队员。