When do we use the present perfect tense?
1) When the accompanying adverb refers to a period gone by, we would use the simple past.
For example: I partied all night last Saturday.
2) With the time period starts from the past and continues to the present, we would use the present perfect.
For example: I have loved my wife from the day I set my eyes on her to now.
3) When we talk about experience and it’s not to describe a specific event, we use present perfect.
For example: I have been to Taiwan.
4) When we talk about an uncompleted action, we use the present perfect.
For example: We haven’t bought our air tickets even though we are heading to Japan tomorrow.
5) If the time market shows "today" or "this month", it’s correct to use either the simple paste or the present perfect.
For example: I exercised/have exercised today.