Complex sentence: In 1996 Aspar started a 18-years long relationship with Aprilia; in those years he fielded riders like Fonsi Nieto and Arnaud Vincent before entering again the 250cc class in 2000 with Alex Debon.
Split into simpler sentences: In 1996 Aspar started a 18-years long relationship with Aprilia; in those years he fielded riders like Fonsi Nieto and Arnaud Vincent. The team entered again the 250cc class in 2000 with Alex Debon.