Ppf
[医][=pellagra preventive factor]抗糙皮病因子，维生素pp
🗣️ 情景例句
You know everyone, Alexandra.
你认识每一位吧 Alexandra。
Such data is confidential.
这样的资料为机密资料。
The girl asked to see a timetable, feeling sure that her father could not have made such a mistake.
姑娘要求看到时刻表，因为她相信父亲不能把这么大的事弄错。