Themes are developed by authors through the following ways: What happens - key events. Characters - character qualities, character actions and how characters respond to situations may all relate to theme. Character development - the ways characters change, and the lessons they learn indicate themes for the reader. The major theme in a literary work is the most significant idea the author is trying to convey. A theme can be anything from “Love and Friendship” to “Good versus Evil.” It's the underlying idea that connects the plot and characters with a deeper meaning.
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