Fluorgypsum
氟石膏
🗣️ 情景例句
and do it while I talk to my secretary.
我去和秘书说个话。
My brother used to speak French to me all the time.
我的兄弟过去总是对我说法语。
he has just bought a new house in the city,
他刚在城里买下一所新房子，