Keep your mouth shut and your ears open.

中文 少说为佳，多听为妙

Kill not the goose that lays the golden eggs.

中文 杀鸡取蛋，愚蠢荒唐

Kill two birds with one stone.

中文 一箭双雕

Kiss and be friends.

中文 吵嘴后，和为贵

Knowledge in youth is wisdom in age.

中文 少时有知识，老来有智慧

Knowledge is a treasure, but practice is the key to it.

中文 知识是宝库，实践是钥匙

Knowledge is power.

中文 知识就是力量

Knowledge makes humble; ignorance make proud.

中文 知识使人谦虚，无知使人骄傲