Learners often make mistakes with the difference between these two tenses. Here are the basic rules:
1. We use the present perfect when it is not important to say exactly when or where something happened:
- I’ve read one of his books. (it doesn’t matter when I read it)
We use the past simple when we specify the time or place that something happened:
- I read one of his books last year.
2. We use the present perfect for actions that have an effect on the present:
- Oh no! I’ve broken my phone. (this happened in the recent past and my phone is broken now)
We use the past simple for actions that are finished and don’t have an effect on the present:
- He dropped his phone on the floor and broke it. (this happened in the more distant past and we are not concerned with any effect on the present)
3. We use the present perfect to talk about finished actions when someone is still alive:
- Alice has been to Scotland several times.
We use the past simple to talk about finished actions when the person is dead:
- Alice went to Scotland several times.
4. We usually use the present perfect with the words ever, never, already, just and yet:
- Have you ever met Lou’s mum?
- He’s already eaten most of the cheese.
Note that there are differences in usage between British and American English. Americans are much more likely to use the past simple in these cases.