[{"role": "user", "content": "I'm trying to explain a situation to an Italian friend, and I'm not sure how to say it - can you help me translate \"She lost a book\" into Italian?"}, {"role": "assistant", "content": "The translation of 'She lost a book' in Italian is 'Lei ha perso un libro.'"}, {"role": "user", "content": "Grazie mille! That's exactly what I needed to know. Can you also tell me if there is a more informal way to say this?"}, {"role": "assistant", "content": "In informal situations, you can use 'Lei' less frequently and simply say 'Ha perso un libro' or 'Ha perso il libro' if you're referring to a specific book."}]