"It's the sadness of childhood" is the best sentence written by a person. The classic comes from the last sentence of Li Qingzhao's "Dianjiang Lip" in the Song Dynasty: Only Wen Qingmei. Li Qingzhao vividly described the delicate and sensitive love of the girl, trying to get close to him, but pretending not to care. Her heart should be sweet fantasy and contradictory. As it happens, this song also shows the obscurity of family, and dare not express it, so it is suffering, like the troubles of young Werther, and it must be sad.