Complex sentence: Costello moved with his Liverpool-born mother to Birkenhead, Cheshire, in 1971 where he formed his first band, a folk duo called Rusty, with Allan Mayes.
Split into simpler sentences: Costello moved with his Liverpool-born mother to Birkenhead, Cheshire, in 1971. There, he formed his first band, a folk duo called Rusty, with Allan Mayes.