This is an English lesson to explain the meaning of the present perfect simple tense and how to use it. I also compare the present perfect to the past simple and explain the differences.The present perfect simple tense is in fact a past tense. We use it to describe an action or event at a non specified time in the past. Usually the action or event has an impact or connection with the present.Example: "David has broken his arm."News reports in the media often use the present perfect at the start of a report to give a general summary.We can use the present perfect with indefinite time adverbs (ever, never, once, before, so far, already, yet, etc)Some common uses of this verb tense are as follows:- to describe experience we have acquired, example "I have learned Japanese."- to describe how a situation has changed or evolved over time, example "The price of bread has increased."- to describe an event that we are expecting or waiting to happen, example "He still hasn't found a job."We can also use the present perfect to describe several actions at different unspecified times in the past. Example: "I have read this book four times."With some specific types of verbs, we can also use the present perfect to express the duration of an action or event. We can do this with "for" or "since." Examples: "I have had this computer for 2 years." Or "I have had this computer since 2012."We can limit the period of the past with unfinished time expressions like: in the last week, this week, today.At the end of this English grammar lesson, I explain the main differences between the present perfect and the past simple tense.