Breakdown of Deves deixar a roupa no balneário, desde que o cacifo esteja vazio.
estar
to be (temporary / location)
em
in / on / at
vazio
empty
o
him/it (m)
Questions & Answers about Deves deixar a roupa no balneário, desde que o cacifo esteja vazio.
Doesn't desde que usually mean 'since'?
It can mean both 'since' and 'provided that', depending on the grammar that follows it! When followed by the normal indicative mood (like desde que cheguei - since I arrived), it talks about time. But when followed by the subjunctive mood, as it is here, it sets up a condition and translates to 'provided that' or 'as long as'.
Why do we use esteja instead of está in this sentence?
Esteja is the present subjunctive form of estar (to be). We must use the subjunctive here because the phrase desde que introduces a condition that must be met. The locker being empty is a requirement for you to leave your clothes, not a stated fact.
Why is it esteja vazio instead of seja vazio?
Even though we are in the subjunctive mood, the rules for choosing between ser and estar still apply. A locker being empty is a temporary condition, not a permanent characteristic. Because it can easily be full or empty at different times, we use estar (which becomes esteja here).
Why is a roupa singular when the English translation says 'the clothes'?
In Portuguese, a roupa is usually treated as a collective noun, much like 'clothing' or 'laundry' in English. While you can say as roupas, it is much more natural to use the singular a roupa when talking about your clothes in a general sense.