Ppf
[医][=pellagra preventive factor]抗糙皮病因子，维生素pp
🗣️ 情景例句
I just solved the mystery.
我刚刚把那个谜底解开了。
Better eye sore than all blind.
眼痛总比瞎眼好。
There is a boy in the water.
河里面有个男孩。