Ppf
[醫][=pellagra preventive factor]抗糙皮病因子，維生素pp
??? 情景例句
It's unsafe for girls to go out alone at night.
女孩子晚上一個人外出很危險的。
He will be indignant about the injustice.
他可能會因不公平的判決而生氣。
but the took a long time to send them Meanwhile,
但過了好長時間不見他把數字寄來，