Simplify the following text for a Grade 11 native English-speaking person.
Original: After winning the Luciano Pavarotti Voice Competition , Alagna made his professional debut in 1988 as Alfredo Germont in La Traviata with the Glyndebourne touring company .
Simplified: He won the Luciano Pavarotti Voice Competition . He started to sing professionally in 1988 singing the part of Alfredo Germont in Giuseppe Verdi 's La Traviata with the Glyndebourne touring opera Soon he was being asked to sing all over the world in opera houses such as La Scala , Covent Garden and the Metropolitan Opera .