This is an irregular verb. It is a model verb.
PresentPresente
Ella abre la ventana todas las mañanas.
She opens the window every morning.
PreteritePretérito indefinido
Ayer abrimos la tienda a las nueve.
We opened the store at nine yesterday.
ImperativeImperativo afirmativo
Abran la ventana un poco, por favor.
Open the window a little, please.
Present SubjunctivePresente de subjuntivo
Espero que abra la ventana.
I hope he opens the window.