Present Perfect Tense can be used in three situations:
1. To indicate something that has happened at an indefinite time in the past.
I have seen that movie already.
She has left for California.
They have not eaten their dinner yet.
2. To indicate something which started in the past and continues until now.
I have lived in New York for nine years.
We have been here since Friday.
He has played football since he was a child.
3. To indicate something which occurred recently.
I have been sick lately.
She hasn’t slept much recently.
When speaking about a specific time, use past tense.
|A: I have seen that movie already.||(Non-specific time)|
|B: Oh really? When did you see it?|
|A: I saw it last week with Bob.||(Specific time)|
Some words should not be used in situation 2 (above)
|I have met John for five years.||(INCORRECT)|
|I have known John for five years.||(CORRECT)|
|I met John five years ago.||(CORRECT)|
|I have met John already.||(CORRECT)|
Sometimes, but not always, present perfect continuous can be used instead of present perfect.
|I have lived there for ten years.||(Okay)|
|I have been living there for ten years.||(Okay)|
|I have exercised a lot recently.||(Okay)|
|I have been exercising a lot recently.||(Okay)|
|I have seen that movie ten times.||(Okay)|
|I have been seeing that movie ten times.||(NOT Okay)|