Ppf
[医][=pellagra preventive factor]抗糙皮病因子，维生素pp
🗣️ 情景例句
Isn't this the Nanjing University?
请问是南京大学吗？
All produets have to go through five checks in the whole process.
所有产品在整个生产过程中得通过五道质量检查关。
(The farmer arrives at the woman's house again.)
（农民再次来到妇女的家。）