I have been searching for the differences between these two tenses. I thought I finally understand them but when I watch a movie, the usage of simple past tense is different than I expected. Most of the time, past simple is used without a time expression. I thought that present perfect should be used if time is not given. (unless you are telling a story about the past) For example in this video: https://www.youtube.com/watch?v=GzFWI8KvGmE&ab_channel=linguaclips I would use present perfect instead of simple past. For example: (Instead of saying Where did everyone go? I would say Where has everyone gone? because there is nobody at home)
The usage of the present perfect in English is one of the subtlest points in English usage.
Time markers usually suggest using the past rather than the present perfect. Here is a counter example
"I have seen him, just yesterday in fact."
Here the present perfect is giving emphasis.
Recency usually suggests present perfect, and lack of relative recency usually suggests the past, regardless of time markers.
"Julius Caesar has invaded England" has no time marker, but an event some 2100 years in the past requires the past tense.
The fact is that the distinction between the two tenses is very hard to reduce to simple rules.
I thought that present perfect should be used if time is not given.
I think that you've got that the wrong way round. If you use present perfect, you should not use a time marker:
I have booked a room on Thursday - incorrect
I booked a room on Thursday - correct
With past simple, you can use a time marker, but it's not required.
I went to see the film on Thursday
I went to see the film that you suggested.
The first sentence reports when something happened. The second sentence affirms that something happened, but does not say when.
According to the British Council, present perfect is used:
- for something that started in the past and continues in the present
- when we are talking about our experience up to the present
and past simple is used:
- for something that happened once in the past
- for something that happened several times in the past
- for something that was true for some time in the past
Note that there is a difference in usage between British English and American English: Americans often use past simple when they consider an action to be completed, whereas British speakers favour present perfect where the action has a lasting effect.
Where did everyone go? - American English
Where has everyone gone? - British English