Why whenever I use sobre in a sentence its followed only by 'la/el'? These examples are taken from the course I'm doing on Duolingo.
E.g. El gato esta sobre la mesa.
But if I use debajo its followed by 'de la/el'.
Mi celular esta debajo de la ropa.
Is there a reason for this?
Why does one use just 'la/el' but the other needs the 'de' to be marked correct?