The document defines different types of sound that can be used in TV dramas, including diegetic sounds that come from within the scene and non-diegetic sounds that come from outside. It provides examples of different sound effects, music, and dialogue that can be used and how they contribute to the atmosphere, mood, and message of a scene. The purpose of sound in TV dramas is also discussed, such as using music, ambient noise, and dialogue to engage the audience and enhance the narrative.