Ppf
[医][=pellagra preventive factor]抗糙皮病因子，维生素pp
🗣️ 情景例句
Just because the other kids have motor scooters is no reason for you to stop riding your bike to school.
只是因为其他的孩子都有电单车上学，不足以成为你不骑车上学的理由。
I'm glad to hear about you passed the test.
我很高兴得知你通过了考试。
The Ombudsman is not subject to political pressure.
司法特派员不受任何政治压力的制约。