Perfluoroalkanes
全氟烃类
🗣️ 情景例句
Will it be too late if I call around 9:00 tonight?
如果我在晚上9点左右打来会不会太晚？
I don't like working on Sunday.
我不喜欢在星期天工作。
The steps are rather narrow.
这些台阶相当窄。