The document discusses the use of the simple past tense in English. It describes four main uses: 1) to express completed actions in the past that occurred at a specific time, 2) to list a series of completed past actions, 3) to describe actions that occurred for a period of time in the past, and 4) to talk about habitual past actions or habits that have stopped. Examples are provided to illustrate each use of the simple past, such as "I saw a movie yesterday" and "I lived in Brazil for two years."