True. A theme in literature can be expressed in a single sentence, providing a concise summary of the author's message or insight. A theme is a universal idea or message that the author is trying to convey through their work. It can be expressed in a variety of ways, including through characters, plot, setting, and symbolism. A theme is not the same as a plot, which is a series of events that make up the story. Instead, a theme is a broader idea that encompasses the entire work. A well-crafted theme can provide readers with a deeper understanding of the work and its significance.