Ppf
[医][=pellagra preventive factor]抗糙皮病因子，维生素pp
🗣️ 情景例句
Believe me, I won't.
放心， 我不会的。
Wickedness does not go altogether unrequited.
恶有恶报。
The bridge is so long that the shape of the earth had to be taken into account by its designer.
由于桥身太长，设计者不得不考虑了地表的形状。