Ppf
[医][=pellagra preventive factor]抗糙皮病因子，维生素pp
🗣️ 情景例句
Great job!
干得好，干得妙！
Is your factory any different from other plastics factories?
你们工厂和其他塑胶工厂有何差别呢？
All these years, Eric had lived as a recluse.
这些年来，埃里克过着隐士生活，