Pellagramin
[医] 烟酸
🗣️ 情景例句
Always full of surprises,
总是出人意表
Friendship cannot stand always on one side.
来而不往非礼也。
With practice, no doubt, I could in time learn to write by holding the pen still while the paper moved.
毫无疑问，经过练习，我最终能够学会笔不动而纸动来写字。