The document is a reading comprehension exercise about MP3 players from an English textbook. It contains a pre-reading section to define MP3 players, a dialogue between a boy and his grandmother comparing two MP3 players, and post-reading comprehension questions. The dialogue takes place when the boy and his grandmother are shopping and see two MP3 players - a purple one and a black one. The grandmother wants to buy the purple one because it works like a tape recorder and is cheaper than the black one. She pays for it with cash.