Nos quedan por comprar las palomitas y algo de beber antes del estreno.

It means something like we still have left to buy.

A very literal breakdown is:

• nos = to us
• quedan = remain / are left
• por comprar = to buy / left to buy

So Nos quedan por comprar... is a common Spanish way to say that some items are still not bought yet.

Because nos and nosotros do different jobs.

• nosotros = the subject pronoun we
• nos = an object pronoun meaning to us or sometimes us

In this sentence, the subject is not we. The thing doing the grammatical action is las palomitas y algo de beber — those are the things that remain.

So the structure is more like:

• To us remain to buy the popcorn and something to drink

That is why Spanish uses nos, not nosotros.

Because the verb agrees with the thing that remains, not with nos.

The subject here is:

las palomitas y algo de beber

That is treated as a plural idea, so the verb is plural:

• queda = singular
• quedan = plural

Even though algo is singular, the full subject is a combination of two things:

• las palomitas
• algo de beber

Together, they make the plural verb quedan sound natural.

Quedar por + infinitive means to remain left to do.

Examples:

• Me queda por estudiar un tema. = I still have one topic left to study.
• Nos queda por reservar el hotel. = We still have the hotel left to book.
• Quedan por corregir muchos exámenes. = Many exams still remain to be corrected.

So in your sentence:

• Nos quedan por comprar... = We still have ... left to buy

It is a very natural structure in Spanish.

Yes, you could, but the meaning is slightly different in tone.

• Tenemos que comprar... = We have to buy...
• Nos quedan por comprar... = We still have ... left to buy

The first focuses on obligation. The second focuses on what is still unfinished on a list.

So nos quedan por comprar suggests that maybe other preparations are already done, and these are the remaining things.

In Spain, palomitas means popcorn, and it is very commonly used in the plural.

This is similar to how some foods are often talked about as plural items even when English may use a mass noun.

So:

• las palomitas = popcorn

In Spain, this is the normal everyday word you would hear at the cinema.

It means something to drink.

This is a very common Spanish pattern:

• algo de comer = something to eat
• algo de beber = something to drink

Here, beber is an infinitive, but after algo de, it works like a general category:

• something for drinking
• more naturally in English: something to drink

Because algo de + infinitive is the usual idiomatic pattern for this idea.

So Spanish commonly says:

• algo de comer
• algo de beber

If you say algo para beber, it sounds less natural in this context, because that can suggest something intended for drinking in a more literal or unusual way. The standard expression for food and drink is algo de comer / beber.

It means before the premiere or before the showing/opening.

A few useful points:

• antes de = before
• el estreno = the premiere, debut, first showing, release

Because de + el contracts, you get:

• de el → del

So:

• antes del estreno = before the premiere / before the screening starts

Depending on context, estreno could refer to:

• the premiere of a film
• the opening night of a play
• the first showing of something new

Yes, in normal Spanish, de + el becomes del.

So:

• antes del estreno comes from
• antes de el estreno

But Spanish does not say de el here; it must contract to del.

One exception to remember in general Spanish is when El is part of a proper name, such as El Escorial:

• de El Escorial
  not del Escorial in that case

But in your sentence, estreno is just a normal noun, so del is required.

It is fairly flexible.

The original order is very natural:

• Nos quedan por comprar las palomitas y algo de beber antes del estreno.

But Spanish could also say:

• Antes del estreno nos quedan por comprar las palomitas y algo de beber.

That just moves the time phrase to the front for emphasis.

What is important is that nos quedan por comprar stays together as a clear verbal structure.

The grammatical subject is:

las palomitas y algo de beber

That is why the verb is quedan.

This can feel strange to English speakers because English would usually make we the subject:

• We still have to buy popcorn and something to drink

But Spanish often structures it differently:

• To us remain left to buy popcorn and something to drink

So the sentence is built around what remains, not around who must do it.

Yes, especially because of palomitas.

In Spain:

• palomitas is the normal word for popcorn

In many Latin American countries, other words are common, such as:

• pochoclo
• cotufas
• crispetas
• palomitas in some places too

The structure nos quedan por comprar is widely understandable across the Spanish-speaking world, but palomitas is a strong Spain-friendly clue.