Breakdown of Antes de salir, mi madre miró si había suficiente gasolina para llegar a la playa.
Questions & Answers about Antes de salir, mi madre miró si había suficiente gasolina para llegar a la playa.
Because after antes de, Spanish uses the infinitive when the subject is the same or when the action is being referred to in a general way.
It works like English before leaving. Spanish often uses antes de + infinitive where English may use either before leaving or before she left, depending on style.