Fluorochemicals
含氟化合物
🗣️ 情景例句
Is he OK?
他还好吗？
Today is the first day of spring.
今天是春天的第一天。
He led me into his room and hurriedly hid a large parcel under his desk.
他把我领进屋，慌忙把一个大包藏到了桌子下面。