Predentin
前期牙(本)质, 原牙质
🗣️ 情景例句
Remember your father-in-law's a pediatrician.
记住你公公是小儿科医师。
A friend in need is a friend indeed.
患难朋友才是真朋友。
They cut big pieces of metal into small pieces.
它们把大块的金属切成小块。