Past Perfect describes something that happened in the past before some other past event, for example: When I came to the party, John had already left. ( it means that John left and then I came to the party) Present Perfect describes something that happened in the past but has consequences in the present, it's always connected with now, for example: I have lost my keys ( I lost it and I still haven't found it)

- past perfect: the action started & finished in the past ex: i had lost my teenage careless attitude since i've known her. - present perfect: the action started in the past & still goes on up till now (moment of speaking) ex: i've had my driving licence 10 years now, and i have one single accident on the records. I hope this will help ;)