What were the functions of secondary characters in prose? Please explain in detail.

Prose is a form of literature, usually expressing the author's thoughts and emotions in a free and undisciplined manner. In prose, secondary characters usually exist to enrich the plot, strengthen the theme, or increase the literary appeal. The following are the common roles of secondary characters in prose: 1. Enriching the storyline: The appearance of secondary characters can enrich the storyline and increase the variety and interest of the novel. For example, in an essay about a family story, one could add one or more secondary characters of the family members to play different roles in the story, such as adding emotional descriptions, expressing the character's personality, and promoting the development of the story. 2. Enhancing the expression of the theme: Secondary characters can use their own experiences, feelings, or opinions to enhance the expression of the theme of the prose. For example, an essay on the subject of love could add a character of a secret admirer or a lovelorn to express the subject of love through their experiences and feelings. 3. Increase the literary appeal: Secondary characters can increase the literary appeal of the prose through their own emotions, thoughts, and actions. For example, in a prose describing a journey, a secondary character of the traveler could be added, allowing their actions and feelings to express the theme of the journey to increase the literary appeal. 4. Pushing the development of the plot: The appearance of secondary characters can promote the development of the plot and make the story more interesting and complete. For example, in an essay that tells a story, you can add a mysterious secondary character to make their appearance and actions promote the development of the story, increasing the mystery and interest of the story. Secondary characters play an important role in prose. They can enrich the plot, strengthen the theme, increase the literary appeal, or promote the development of the plot through their own experiences, feelings, or opinions.