to have made a mistake
Loro devono aver fatto un errore.
They must have made a mistake.
Solo in quel momento capì di aver fatto un errore grave.
Only then did he realize he had made a serious mistake.
Ha riconosciuto di aver fatto un errore.
He acknowledged that he had made a mistake.
I must have made a mistake.
Realizza di aver fatto un errore.
You realize that you made a mistake.
Io posso aver fatto un errore.
I may have made a mistake.
They must have made a mistake.
Ammetto di aver fatto un errore.
I admit I made a mistake.
He must have made a mistake.