To say that something or someone is the smallest or the most beautiful, use le plus, la plus, or les plus before an adjective.
C’est le plus petit chien !
He’s the smallest dog.
Mon village est le plus joli de France.
My village is the prettiest in France.
C’est la plus belle femme du monde !
She’s the most beautiful woman in the world.
Ces chiens sont les plus rapides.
These dogs are the fastest.
To say that you hear something, use du, de la or des before the thing that you're hearing.
J'entends de la musique.
I hear music.
Tu entends du bruit ?
Do you hear some noise?
J’entends des bruits !
I hear noises!
Nous entendons des chouettes la nuit.
We hear owls at night.