Complex sentence: The Prix Royal-Oak is a Group 1 flat horse race in France for three-year-old and above thoroughbreds run over a distance of 3,100 metres (approximately 1 mile 7½ furlongs) at Longchamp Racecourse in October.
Split into simpler sentences: The Prix Royal-Oak is a Group 1 flat horse race in France for three-year-old and above thoroughbreds. It is run over a distance of 3,100 metres (approximately 1 mile 7½ furlongs) at Longchamp Racecourse in October.