The fill-in of a novel referred to the unfinished story content at the end of the novel that needed to be supplemented and perfected by the author. This kind of behavior was usually to leave more space for the reader to imagine and think so that the reader could better understand the theme and plot of the novel. The King of Traps referred to an author who wrote novels that often had some problems that could not be filled in. In other words, the plot was incomplete or there were many unknown factors, which usually caused the readers to be disgusted and dissatisfied. Some cheat kings even deliberately left some open-ended endings for the readers to imagine and guess. This behavior was called an " open-ended ending." In general, the author had to pay attention to the problem of filling in the pit and the king of the pit when writing a novel. The author had to leave as much room for the reader's imagination as possible while ensuring that the story was complete, reasonable, and logically rigorous.