Quan acabis els deures, esborra el primer paràgraf i copia només la resposta correcta al quadern.

Because quan often takes the present subjunctive in Catalan when it refers to a future action.

So:

Quan acabis els deures...
means When you finish your homework...

Here, the finishing has not happened yet, so Catalan uses acabis rather than the indicative form acabes.

A useful contrast:

• Quan acabis, avisa’m = When you finish, let me know
• Quan acabes els deures, sempre descanses = When you finish your homework, you always rest / Whenever you finish your homework, you always rest

So acabis signals a future, not-yet-completed action.

In Catalan, deures is normally plural when it means homework.

So els deures is the usual way to say homework or the homework in a school context.

The singular deure usually means duty or obligation, although it can sometimes mean a single assignment in certain contexts.

The article els is also normal. Catalan uses definite articles more often than English does. English often says just homework, but Catalan naturally says els deures.

Yes. Both are affirmative imperative forms for tu:

• esborra = erase
• copia = copy

So the sentence gives two instructions:

• esborra el primer paràgraf
• i copia només la resposta correcta al quadern

These are the informal singular commands, used when speaking to one person as tu.

Because Catalan often omits subject pronouns when they are already clear from the verb form.

In commands, this is especially normal.

So instead of saying:

Tu, esborra...

Catalan usually just says:

Esborra...

The verb form already shows that the speaker is addressing you informally.

Because articles and adjectives must agree with the noun in gender and number.

• paràgraf is masculine singular, so you get el primer paràgraf
• resposta is feminine singular, so you get la resposta correcta

That is why:

• primer is masculine
• correcta is feminine

This kind of agreement is very important in Catalan.

Here només means only, and it limits la resposta correcta.

So the idea is:

copy only the correct answer

It tells you not to copy anything else.

Its position is important. In this sentence, només goes right before the thing being restricted:

copia només la resposta correcta

That is the most natural placement here.

Al is the contraction of a + el.

• a = to / in / into
• el quadern = the notebook

So:

al quadern = to the notebook or more naturally in the notebook / into the notebook

With verbs like copiar, Catalan often uses a to show the place where something is written or copied.

So copia ... al quadern means copy ... into the notebook.

Catalan uses written accents to show stress and sometimes vowel quality.

• només has an accent to show the stressed syllable: no-més
• paràgraf has an accent to show the stress falls on pà: pà-ra-graf

These accents are part of the standard spelling and are important to learn, because stress in Catalan is not always predictable from English habits.

Usually, yes. Quadern means a notebook or exercise book, especially in a school context.

In this sentence, it strongly suggests the student’s notebook where they are supposed to write their answer.

Depending on context, Catalan can also use words like llibreta, but quadern is a very common school word.