Se o baloiço estiver molhado, ela prefere correr até ao escorrega.

Because Portuguese normally uses the future subjunctive after se when talking about a possible future condition.

So:

Se o baloiço estiver molhado...

is the natural way to say:

If the swing is / happens to be wet...

This is different from English, which usually just uses the present tense after if.

Sometimes, yes, but it changes the feel.

• Se o baloiço estiver molhado = an open future possibility
• Se o baloiço está molhado = more like a present fact or a repeated situation, often close to whenever the swing is wet

So in a standard conditional sentence about what will happen in that situation, estiver is the better choice.

Estivesse is the imperfect subjunctive, which usually makes the condition sound more hypothetical, less real, or contrary to fact.

Compare:

• Se o baloiço estiver molhado... = if it turns out to be wet
• Se o baloiço estivesse molhado... = if it were wet

With estivesse, the main clause would usually change too, for example:

Se o baloiço estivesse molhado, ela preferia / preferiria correr até ao escorrega.

So estiver is the right match for the sentence you were given.

Yes. Baloiço is the usual European Portuguese word for a playground swing.

This is one of the words that clearly points to Portugal rather than Brazil. In Brazilian Portuguese, balanço is more common for this meaning.

So if you see baloiço, that is a strong European Portuguese clue.

Because adjectives in Portuguese agree with the noun they describe in gender and number.

Here, baloiço is masculine singular, so the adjective must also be masculine singular:

• o baloiço molhado

If the noun were feminine, you would use molhada:

• a cadeira molhada

If it were plural:

• os baloiços molhados

Yes, Portuguese often drops subject pronouns when the subject is clear from the verb or from context.

So this would also be possible:

Se o baloiço estiver molhado, prefere correr até ao escorrega.

The pronoun ela is included for reasons like:

• clarity
• emphasis
• contrast with someone else
• reminding the listener who the subject is

So ela is not wrong or unusual; it just makes the subject more explicit.

Because in Portuguese, after many verbs, the next verb goes directly in the infinitive.

So:

• prefere correr = prefers to run
• quer brincar = wants to play
• gosta de ler = likes to read

In English, you often need to before the second verb. In Portuguese, you often do not.

With preferir, the pattern is commonly:

• preferir + infinitive
• preferir X a Y when comparing two things

So ela prefere correr is completely normal.

Here, até means as far as or to, marking the end point of movement.

So:

correr até ao escorrega

means running to the slide.

But até can also mean until, especially with time:

• até amanhã = until tomorrow
• até às cinco = until five o’clock

So the meaning depends on context. In this sentence, it is about movement toward a place, not time.

Ao is the contraction of:

a + o = ao

Here, o is the masculine singular definite article for escorrega.

So:

• ao escorrega = to the slide

In European Portuguese, até ao is very common before a masculine singular noun with the article.

Yes, escorrega can be a verb form of escorregar meaning he/she slips.

But in this sentence, o escorrega is a noun, meaning the slide in a playground.

The article o makes that clear.

This is also a good reminder that Portuguese nouns do not always follow the most obvious ending pattern:

• escorrega ends in -a
• but it is still masculine: o escorrega

That is normal in Portuguese. There are other masculine nouns ending in -a too, such as o dia and o mapa.

Portuguese uses definite articles very naturally with specific nouns, often more regularly than English learners expect.

Here, the sentence is referring to identifiable playground equipment, so:

• o baloiço = the swing
• o escorrega = the slide

That sounds completely natural in Portuguese.

Even when English might sometimes be a bit looser with articles, Portuguese often prefers to include them.