Learn Italian: Ci sono voluti tre mesi per superare i quiz teorici. - It took three months to pass the theoretical quizzes.

With the verb volerci (to take time), the amount of time is actually the grammatical subject. Because tre mesi (three months) is masculine plural, the auxiliary verb must be sono and the past participle must end in -i to agree with it (voluti).

How would this sentence change if I used metterci instead of volerci?

If you use metterci, the person taking the time becomes the subject, and it uses the auxiliary avere. You would say Ci ho messo tre mesi per superare i quiz teorici (I took three months...). The past participle messo does not change to match the months.

Why use superare instead of passare for 'to pass'?

While you might hear passare, superare (which literally means 'to overcome') is the standard and most natural verb in Italian for successfully passing an exam, test, or quiz.

Why doesn't the word quiz change in the plural?