Present perfect or past simple

The present perfect, have or has plus the past participle, links the past to now: I have lost my keys (they are still lost), she has lived here for ten years (she still does).

Use the past simple with a finished time, yesterday, last year, in May: I lost my keys yesterday. Never put a finished time with the present perfect: I have seen him yesterday is wrong.

For gives a length of time, since a starting point: for three years, since June. Ever, never, already, yet and just usually go with the present perfect.