The document discusses the differences between the past simple and past continuous tenses in English. The past simple is used to describe completed actions in the past, often followed by time expressions like "yesterday" or "last week." The past continuous describes ongoing or incomplete actions happening in the past, often used with time expressions like "at 10:00" or "yesterday evening." Examples are provided for how to use each tense individually and together to describe actions that happened simultaneously or where one action interrupted another.