This document discusses various tenses in English including the past perfect, present perfect, and future perfect tenses. It provides examples and explanations of when to use each tense. The past perfect tense expresses an action that was completed before another past action. The present perfect tense is used for actions that began in the past and continue in the present or are completed but relevant in the present. The future perfect tense expresses an action that will be completed before a specified time or event in the future.