凡事都是对立统一的。人的皮肤亦如是，既需要搽脂抹粉，也需要去污脱垢。用在教育上，搽脂抹粉好比鼓励、表扬、戴花，而去污脱垢则好比批评、鞭策、栽刺。前者令人愉快，后者让人耳热心跳。但不管主观感觉如何，二者都是客观需要，尤其是后者，因阻抗大，接受起来相当难，所? Everything is opposites. Human skin is also true, both need to grease grease, but also decontamination. Used in education, paint grease like to encourage, praise, wearing flowers, and decontamination is like criticism, spurring, planting thorns. The former is delightful, the latter ear-hearted. However, no matter what the subjective feeling is, both are objective needs. In particular, the latter are quite difficult to accept due to their large impedance.