Ppf
[医][=pellagra preventive factor]抗糙皮病因子，维生素pp
🗣️ 情景例句
When do you need the volunteers,
你们什么时候需要义工
No, I'll move to Hollywood next month.
不，我下个月搬到好莱坞去。
Despite its immensity,
尽管此桥很大，