Fluocarbon
氟代烃
🗣️ 情景例句
But some things are personal or private, and questions about them are not polite.
但是有些事是私人的，问这些方面的问题是不礼貌的。
He who does no good, does evil enough.
好事不做，坏事做绝。
Broadly speaking, human beings may be divided into three classes: those who are toiled to death,
劳累至死的人、