2. This technique comes from "Bi" and "Xing" in The Book of Songs. Ode to the Orange is an ancient masterpiece that uses metaphor throughout. Since then, it has become one of the commonly used techniques in poetry and prose. Generally, it is used to praise beautiful things and reflect the author's pursuit of ideal realm, but sometimes it can also be used to satirize ugly things and attack unreasonable phenomena. Can be used throughout, the author did not point out, but readers can understand the meaning of symbols themselves, can also be used only for some chapters and fragments, the author can directly point out the meaning of symbols.