Ci vogliono poche ore per preparare la cena.

Because the real subject of volerci here is poche ore, which is plural.

• Ci vuole
  • singular noun
    
    • Ci vuole un’ora = It takes an hour
• Ci vogliono
  • plural noun
    
    • Ci vogliono poche ore = It takes a few hours

So the verb agrees with ore, not with preparare.

Not exactly. This is the expression volerci, which means to be needed / to take (time, effort, etc.).

So in this sentence:

• Ci vogliono poche ore = A few hours are needed / It takes a few hours

This is different from normal volere meaning to want.

Compare:

• Voglio un caffè. = I want a coffee.
• Ci vuole pazienza. = Patience is needed.
• Ci vogliono due giorni. = It takes two days.

In this expression, ci is part of the idiomatic structure volerci. It does not translate neatly as one single English word in this sentence.

You should learn:

• ci vuole
• ci vogliono

as fixed patterns meaning:

• it takes
• it is needed
• you need

depending on context.

So in Ci vogliono poche ore, ci is not really us or there in the usual sense. It is just part of the expression.

Poche means few and agrees with ore, which is feminine plural.

The noun is:

• ora = hour
• ore = hours

Since ore is feminine plural, the adjective must also be feminine plural:

• poche ore = a few hours

Compare:

• poco tempo = a little time
• pochi minuti = a few minutes
• poche ore = a few hours

This phrase expresses purpose or what the time is needed for.

• per = to / in order to / for
• preparare = to prepare
• la cena = dinner

So:

• Ci vogliono poche ore per preparare la cena
  = It takes a few hours to prepare dinner

You can think of per + infinitive as a very common Italian structure meaning to do something or in order to do something.

Examples:

• Serve tempo per capire. = Time is needed to understand.
• Ci vuole pazienza per insegnare. = It takes patience to teach.

In this sentence, per preparare is the natural choice.

With expressions like ci vuole / ci vogliono, Italian commonly uses per + infinitive to explain what is required or what the time is for:

• Ci vogliono due ore per finire il lavoro.
• Ci vuole coraggio per dirlo.

Using a preparare here would not sound natural in standard Italian.

Because after ci vuole / ci vogliono, the usual pattern for expressing the action is:

• ci vuole / ci vogliono + noun + per + infinitive

So:

• Ci vogliono poche ore per preparare la cena is correct.

Italian does use a + infinitive in other structures, but not normally in this one.

Yes. Italian word order is flexible, though some versions are more neutral than others.

Neutral order:

• Ci vogliono poche ore per preparare la cena.

You may also hear:

• Per preparare la cena ci vogliono poche ore.

This version puts the focus first on preparing dinner.

Both mean the same thing. The original sentence is very natural and standard.

Normally, no. In this expression, ci is part of volerci, so you usually need it.

Correct:

• Ci vuole tempo.
• Ci vogliono tre persone.

Without ci, the sentence would either be wrong or sound like a different use of volere.

For example:

• Vogliono poche ore would usually mean they want a few hours, not it takes a few hours.

Yes. If the thing needed is singular, you use ci vuole.

Examples:

• Ci vuole un’ora per preparare la cena. = It takes an hour to prepare dinner.
• Ci vuole poco tempo per preparare la cena. = It takes little time to prepare dinner.

Plural:

• Ci vogliono poche ore per preparare la cena.

So the choice between vuole and vogliono depends on whether the noun that follows is singular or plural.

Yes, that is a good literal way to understand the structure.

Grammatically, Italian is built more like:

• Ci vogliono poche ore
  = A few hours are needed

Natural English usually says:

• It takes a few hours to prepare dinner.

So the literal translation helps you see the grammar, even if the most natural English translation uses it takes.

La cena usually means dinner or the evening meal.

So depending on context, the sentence could refer to:

• preparing dinner
• preparing the evening meal

In most learner contexts, dinner is the best translation.

By itself, it most naturally sounds like a general statement or an estimate:

• It takes a few hours to prepare dinner.

But context can make it refer to a specific situation too:

• Per stasera ci vogliono poche ore per preparare la cena.

Without extra context, the sentence is simply stating how much time is needed.