to have left it
Debo de haberlo dejado en el lugar equivocado.
I must have left it in the wrong place.
I thought I made that clear.
Debo haberlo dejado en el autobús.
I must have left it on the bus.
Alguien debe haberlo dejado ahí.
Someone must have left it there.
No puede haberlo dejado en el aeropuerto.
He can't have left it at the airport.