The audio says "Scrivo un libro".
Not sure about that, but it is pretty garbled.
When words ending in a vowel lead into a word starting with a similar vowel sound, the ending vowel of the lead word is dropped. Therefore, you hear " Scrivon' un libro."
It is clearer when spoken slowly
Scrivono un libro
To me it sounds like the audio is saying "Scrivono libro".
There is no "loro"!! It shoudn't ask for the "they"!!