If you don’t know, ask, and if you don’t know, learn. This means that if you don’t know something, you should humbly ask others for advice, and if you don’t understand something, you should study in depth. Educate students to ask if they don’t understand, and develop the good habit of being diligent in learning and asking questions. After learning, you will not know enough, and after teaching, you will be trapped. If you don’t know, then ask, if you can’t, then learn. Even if you can not give in, then you will be virtuous. If you hear it but don't see it, even if you know it, you will be wrong; if you see it but don't know it, even though your knowledge is not false; if you know it but don't act it, even if you are diligent, you will be trapped. ——Xun Kuang, thinker and educator during the Warring States Period