what happened/what has happened?

Could you tell me the difference between 'what happened?' and 'what has happened?' please :)

Dokładnie taka jak między czasem Past Simple a Present Perfect :)

z perfectem mozna by rzec, ze udzielaja ci sie emocje - poczucie bezposredniosci przekazu

>Could you tell me the difference between 'what happened?' and 'what
>has happened?' please :)

'what happened?' means "what happened then?" "Then" is a point in time in the PAST.

'what
>has happened?' really means "what's the situation now as a result of what happened then?"