Those chalky-white mustaches that color our lips after chugging down a refreshing ice-cold glass of creamy milk is caused by the protein called Casein.

• 灌下一杯新鲜冰冷的牛奶之后，嘴唇和胡子都变得粉白。这是由牛奶中一种叫做干酪素的蛋白质造成的。