The document discusses audio-visual (A/V) aids used in classroom instruction. It defines A/V aids as training or educational materials that target both hearing and sight, such as films and recordings. The document then discusses the importance of A/V aids according to a 2011 U.N. declaration, and classifies A/V aids into three types: audio aids, visual aids, and audio-visual aids. Examples are provided for each type. Advantages of A/V aids include enhancing the speaker's perception, helping the audience remember topics, and making topics more interesting. The document concludes with guidance for class teachers and head teachers on effectively selecting and using A/V aids.