English grammar can be tricky for speakers of other languages, and two tenses which often cause confusion are the past simple and the present perfect. Some people overuse the past simple when they should be using the present perfect, and other people are unsure when to use one or the other.
The past simple refers to something which occurred in the past and has no connection with the present. The action or event could have happened once in the past (I went to Budapest last year) or been continuous or repeated (Dinosaurs lived on the earth). The time can be specified (Where did you go last night?) or not (She worked at the local cinema). The important thing to remember is that the action or event has finished and that we are focusing on a specific time in the past, even if that time is not specified.
The present perfect connects the past to the present; we are thinking about the past and the present at the same time, although the focus is mainly on the present because it is a ‘present’ tense. The action or event started in the past and may have finished (I have written you an email) or it might still be continuing (I have lived in London since 2004). It may have happened in the recent past or it could have occurred a long time ago.
The present perfect refers to something which happened at a point in time before now. The exact time the action or event occurred is not important and, in fact, we cannot say exactly when it happened. Even if we do not mention the specific time, but are just thinking of it, we cannot use the present perfect; instead we would use the past simple:
Have you seen Master Chef (in general on television)?
Did you see Master Chef (last night on television)?
However, we can use unspecific time expressions with the present perfect (e.g. lately, so far, many times, ever, never, since, etc.) or time expressions that describe a period that is not finished (e.g. this month, today, etc.).
Listening to the news you will hear examples of the past simple and the present perfect. The news is often introduced using the present perfect, announcing a past event which is considered relevant at the present time (A man has been rescued). However, when the details of the event are described, the past simple is used, together with expressions of time and place, in order to place it in the definite past (The man’s boat sank yesterday evening).
While we’ve only covered the basics here, if you want to learn more look at a good grammar book such as Michael Swan’s ‘Practical English Usage’ and remember that practice makes perfect!