Prima che gli ospiti si siedano, condisco il cetriolo e la mozzarella con olio e basilico.

Before the guests sit down, I dress the cucumber and the mozzarella with oil and basil.

Breakdown of Prima che gli ospiti si siedano, condisco il cetriolo e la mozzarella con olio e basilico.

• io: I
• con: with
• e: and
• l'ospite: the guest

Questions & Answers about Prima che gli ospiti si siedano, condisco il cetriolo e la mozzarella con olio e basilico.

Why is prima che used here instead of prima di?

Use prima che when it is followed by a full clause with its own subject and a conjugated verb:

prima che gli ospiti si siedano

Use prima di when it is followed by an infinitive, usually when the subject stays the same:

Prima di sedermi, preparo la tavola.

So in this sentence, gli ospiti are the subject of the second action, so prima che is the correct choice.

Why is si siedano in the subjunctive?

Because prima che normally requires the subjunctive in Italian.

This is standard grammar: after prima che, the action is seen as something that has not happened yet at the moment of the main action. So Italian uses the subjunctive even if there is no real doubt.

That is why you get:

prima che gli ospiti si siedano

not standard prima che gli ospiti si siedono.

What is the si doing in si siedano?

It is part of the reflexive verb sedersi, which means to sit down.

So:

• sedersi = to sit down
• si siedano = that they sit down

The si matches gli ospiti because the guests are doing the action to themselves, in the sense of taking a seat.

Why is the form siedano and not something more regular?