The document provides an overview of when to use the present simple tense in English. It lists 4 main contexts: 1) for facts or general truths, 2) for more or less permanent situations, 3) for habits or routines, and 4) to describe feelings or thoughts. Examples are given for each context, such as "Water is transparent" and "On Mondays I finish school at 5 o'clock." The present simple is used to talk about things that happen regularly or are always true.