Pon la mesa antes de que lleguen mis padres.

Pon is the tú imperative of poner (to put / to set).

• poner → pon = set / put
• This is an irregular command in Spanish.

For tú, some common irregular affirmative commands are:

• decir → di
• hacer → haz
• ir → ve
• poner → pon
• salir → sal
• ser → sé
• tener → ten
• venir → ven

So Pon la mesa means Set the table.

Spanish usually leaves out subject pronouns when they are obvious from the verb form or context.

So instead of saying:

• Tú pon la mesa

Spanish normally just says:

• Pon la mesa

The verb pon already shows that the speaker is talking to you informally.

Including tú is possible, but it usually adds emphasis, contrast, or emotion.

Literally, yes, poner often means to put, but poner la mesa is an idiomatic expression meaning:

• to set the table

So in this sentence, Pon la mesa does not mean physically moving a table. It means putting out plates, cutlery, glasses, etc.

This is a very common everyday expression in Spanish.

Because the sentence is followed by a conjugated verb: lleguen.

Spanish commonly uses:

• antes de + noun/infinitive
• antes de que + subjunctive verb

Examples:

• Antes de salir = Before leaving
• Antes de la cena = Before dinner
• Antes de que lleguen mis padres = Before my parents arrive

So here, since there is a full clause with its own verb (lleguen), antes de que is the correct structure.

Because antes de que normally triggers the subjunctive when it refers to an action that has not happened yet.

In this sentence:

• Pon la mesa antes de que lleguen mis padres

the parents have not arrived yet. Their arrival is a future event from the speaker’s point of view, so Spanish uses the subjunctive:

• lleguen

This is one of the most common uses of the subjunctive: after conjunctions like antes de que, when the action is pending or anticipated.

Because after antes de que, Spanish uses the subjunctive, not the indicative.

• llegan = present indicative
• lleguen = present subjunctive

So:

• antes de que llegan ❌
• antes de que lleguen ✅

Even though English says before my parents arrive, Spanish grammar requires the subjunctive here.

Because the subject is mis padres = my parents, which is plural.

So the verb has to agree with the subject:

• mi padre llega = my father arrives
• mis padres llegan / lleguen = my parents arrive

Here it is subjunctive plural:

• lleguen

Yes. That is completely correct.

Both are natural:

• antes de que lleguen mis padres
• antes de que mis padres lleguen

Spanish word order is often more flexible than English. The version in your sentence is very natural, especially because Spanish often places the verb before the subject in subordinate clauses.

There is little difference in meaning. It is mostly a matter of style, rhythm, or emphasis.

Because in Spanish, a possessive adjective like mi, mis, tu, su, nuestro normally comes instead of the article, not with it.

So you say:

• mi madre
• mis padres

not:

• la mi madre ❌
• los mis padres ❌

This is different from some older forms or some other Romance languages, but in modern standard Spanish, mis padres is correct.

Yes. In normal modern Spanish, mis padres means my parents.

Related words:

• mi padre = my father
• mi madre = my mother
• mis padres = my parents

So in this sentence, it clearly refers to both parents.

Yes. That is a very good English equivalent, especially in British English.

Possible translations include:

• Set the table before my parents arrive.
• Lay the table before my parents arrive.

The Spanish structure stays the same, but English may choose different natural expressions depending on region.

If you were speaking to usted instead of tú, the command would change:

• Ponga la mesa antes de que lleguen mis padres.

Comparison:

• Pon = informal singular (tú)
• Ponga = formal singular (usted)

If you were speaking to several people in Spain (vosotros), it would be:

• Poned la mesa antes de que lleguen mis padres.

So the part that changes is the command verb, not antes de que lleguen mis padres.