Bixing is a common skill in ancient poetry. In this regard, Zhu had a more accurate explanation in Song Dynasty. He thinks: "If you compare, compare this thing with another thing", and "If you are interested, say something else first to arouse the words you sing." Generally speaking, "bi" is a metaphor, a metaphor that visualizes people or things, making its characteristics more distinct and prominent. "Xing" is rising, that is, taking other things as the starting point of poetry and arousing the content to be praised. "Bi" and "Xing" are commonly used.