Breakdown of Al romper el cofre, encuentras la espada.
encontrar
to find
romper
to break
al
upon / when (+ infinitive)
el cofre
the chest
Questions & Answers about Al romper el cofre, encuentras la espada.
Why do we use al romper instead of cuando rompes?
Since romper is in its infinitive form, how do we know who is breaking the chest?
Where does the word al come from in this structure?
Al is simply the mandatory contraction of the preposition a and the word el. While it usually means 'to the', whenever you place al directly in front of an infinitive verb, it creates this special time clause meaning 'upon doing' or 'at the moment of doing' something.
A quick refresher: why does encontrar become encuentras here?
The verb encontrar (to find) is a stem-changing verb. In the present tense, the o in the root changes to ue for most subjects, including the tú form used in this sentence.