Why should the role of Peking Opera be divided into life and ugliness?

"Sheng": It is the hero. Generally, junior students wear blue clothes, while senior students wear black clothes. Generally speaking, the old students are mainly singers, and there is also a kind of old workers who are good at reading the white words and expressions, with Zhou Xinfang as the representative. "Dan": The heroine. Generally, Hua Dan wears red or pink clothes, Tsing Yi wears blue and black, Lao Dan wears grayish yellow and Wu Dan wears blue. Lao Dan refers to the average elderly woman, who sings and recites in a true voice, which is similar to that of an old student, and whose movements are feminine than those of a living angle. Hua Dan represents a lively, naive and provocative young woman. Her clothes are mainly jackets and trousers, and her performance focuses on Beijing and white and various movements. Wu Dan refers to a female character who knows martial arts. There is also a new business "Flower Shirt" which breaks the boundary between Tsing Yi and Hua Dan, has the characteristics of both and absorbs the characteristics of peking opera blues. Its creators are Mei Lanfang and Wang Yaoqing. "Net": it is painted with many colors, Guan Gong is red-faced and blue-robed, and Zhang Fei is black-faced and black-robed. Generally, the upright face is mainly black, while the treacherous face is mainly white. Its representative figure is Yuan Shihai. The net performance form is very exaggerated, and the makeup of the face will have different patterns according to different characters. "Ugly": A clown, usually with a white nose. Ugliness can be divided into three types: Wu Ugliness, Wen Chou Ugliness and General Ugliness.