This document discusses the present perfect simple and present perfect continuous tenses in English. It explains that the present perfect simple is used to talk about actions or experiences that began in the past and are still relevant now. It provides examples using words like "yet", "already", and "ever". The present perfect continuous emphasizes the ongoing or unfinished nature of an action and duration is often included using words like "for" or "since". The key difference is that the simple form focuses on completion while the continuous form focuses more on the ongoing process.