Quando torniamo, la maestra ci chiede quale animale abbiamo preferito, e io rispondo: la mucca e il vitello.

In Italian, the present tense is often used for actions that happen regularly, in a sequence, or even in the near future.

So Quando torniamo can mean:

• When we come back
• When we get back
• When we return

Here it fits a kind of storytelling present or routine present:

• first we return,
• then the teacher asks,
• then I answer.

That is why the sentence uses torniamo, chiede, and rispondo all in the present.

Ci means to us here.

So:

• la maestra chiede = the teacher asks
• la maestra ci chiede = the teacher asks us

It is an indirect object pronoun.

A very literal breakdown is:

• la maestra = the teacher
• ci = to us
• chiede = asks

So Italian says something closer to the teacher asks us.

Both quale animale and che animale can mean which animal / what animal in many contexts.

But there is a slight difference in feel:

• quale animale sounds a little more specific or careful
• che animale is often a bit more informal and common in speech

In this sentence, quale animale is perfectly natural and slightly more precise.

Because the question is phrased as which animal did we prefer? — singular.

That suggests the teacher is asking for one favorite animal.

However, the answer la mucca e il vitello gives two animals. That can still happen in real language:

• the speaker may be giving more than one favorite
• the speaker may be answering a bit freely rather than strictly following the singular question

If the teacher clearly expected more than one animal, Italian would more naturally say:

• quali animali abbiamo preferito

Abbiamo preferito is the passato prossimo and means something like:

• we preferred
• we liked best
• we ended up preferring

It is used because the preference refers to a completed experience in the past, probably after seeing the animals.

Compare:

• preferiamo = we prefer / we like better now, in general or in the present
• preferivamo = we were preferring / we used to prefer, which usually gives a more ongoing or background idea
• abbiamo preferito = completed choice or preference after the event

So if the class has already visited the animals and is now talking about that finished experience, abbiamo preferito is the natural choice.

Because with avere, the past participle usually does not agree with the thing liked or chosen.

So:

• abbiamo preferito la mucca
• abbiamo preferito il vitello

The participle stays preferito.

Agreement sometimes happens when a direct object pronoun comes before the verb, but that is a more advanced point. In this sentence, the normal form is simply preferito.

Because it is an indirect question, not a direct one.

Direct question:

• Quale animale abbiamo preferito?

Indirect question:

• La maestra ci chiede quale animale abbiamo preferito.

In English this works the same way:

• direct: Which animal did we prefer?
• indirect: The teacher asks us which animal we preferred.

So no question mark is needed inside the sentence.

Italian often uses definite articles with nouns in places where English would not.

So Italian naturally says:

• la mucca
• il vitello

Even when simply naming things as an answer, Italian often keeps the article.

English might just say:

• the cow and the calf or sometimes simply
• cow and calf

But in Italian, la mucca e il vitello sounds more complete and natural.

In Italian, when talking about a person by their role or title, it is very common to use the article.

So:

• la maestra = the teacher

Italian usually prefers the article here when speaking about her.

But when speaking to her directly, you normally do not use the article:

• Maestra, posso entrare?

So:

• la maestra ci chiede = talking about her
• Maestra! = calling her directly

The colon introduces the exact answer that follows.

So:

• e io rispondo: la mucca e il vitello

This is like writing:

• and I answer: the cow and the calf

It is a neat written way to present direct speech or a direct reply without using a full quoted sentence.

You could also say:

• e io rispondo che abbiamo preferito la mucca e il vitello

But that changes the structure a little. The version with the colon sounds like the speaker is giving the answer directly, exactly as said.