Depois do recreio, nós voltamos para a sala e estudamos para o exame.

Because do is the normal contraction of de + o in Portuguese.

So:

• de + o = do
• de + a = da
• de + os = dos
• de + as = das

After depois de, this happens very often:

• depois do recreio = after recess
• depois da aula = after class

In standard Portuguese, de o recreio would sound wrong here.

In a school context, recreio usually means recess, break time, or playtime.

So depois do recreio means after recess / after the break.

In context, it can refer to:

• the time of the break
• sometimes, by extension, the school playground area

But in this sentence, the most natural meaning is the break period at school.

Yes. Portuguese often leaves out subject pronouns because the verb ending usually shows who the subject is.

So both of these are possible:

• Nós voltamos para a sala...
• Voltamos para a sala...

Both can mean we returned / we return to the classroom...

Including nós can:

• add emphasis
• make the subject extra clear
• sound slightly more explicit

European Portuguese drops subject pronouns very often, so leaving out nós would be completely natural.

Yes—if the intended meaning is the simple past in European Portuguese, the usual spelling is:

• voltámos
• estudámos

That is an important point for a learner of Portuguese from Portugal.

In European Portuguese:

• voltamos / estudamos normally look like present
• voltámos / estudámos are the usual written past forms

So, for Portugal Portuguese, if the sentence means After recess, we returned to the classroom and studied for the exam, many teachers and books would write:

Depois do recreio, nós voltámos para a sala e estudámos para o exame.

As written without the accents, it may look present-tense to a Portugal Portuguese learner.

Yes, Portuguese often contracts prepositions with articles, but para + a is a special case.

In standard writing, it is normally written as:

• para a sala
• para o exame

Not as one mandatory contraction like de + o = do.

In informal speech, you may hear reduced forms such as:

• pra
• pro

But for a learner, especially in standard written Portuguese, it is safest to use:

• para a
• para o

So para a sala is completely normal.

Because it has two different functions here.

1. voltar para a sala
   Here para shows direction/destination: back to the classroom.

2. estudar para o exame
   Here para shows purpose/goal: study for the exam, meaning in preparation for it.

So even though the same word appears twice, it is doing two slightly different jobs.

Yes, sala by itself can mean room, but in a school context it very often means classroom.

That is why:

• voltar para a sala

naturally means:

• go back to the classroom

If you want to be more explicit, you can say:

• sala de aula = classroom

But in everyday school situations, just a sala is often enough.

Yes. Both are possible.

• voltámos para a sala
• voltámos à sala

Both can mean we went back to the classroom.

A useful point:

• à = a + a

So à sala is a contraction.

The difference is usually small:

• para a sala emphasizes movement toward that place
• à sala is a more compact way to say to the classroom

In real usage, both are natural, though para a sala may feel especially straightforward for learners.

Portuguese uses definite articles more often than English.

So when the speaker and listener both know which exam is meant, o exame is very natural:

• estudar para o exame = study for the exam

English often omits articles where Portuguese keeps them, but in Portuguese this sounds normal and specific. It suggests a particular exam the students already know about.