This document discusses verb tenses in English. It explains that tenses can be classified based on time frame (present, past, future) or aspect (simple, continuous, perfect, perfect continuous). There are 12 possible tenses that combine these classifications. The document provides definitions and examples of each tense, such as using the present continuous to emphasize ongoing actions and the past perfect to refer to completed past actions. It concludes with a table summarizing the forms and definitions of all 12 tenses.