Complex sentence: The Sydney Cup is an Australian Turf Club Group 1 Thoroughbred handicap horse race, for three year olds and older, run over 3200 metres at Randwick Racecourse in Sydney, Australiain the autumn during the ATC Championships series and it is the longest race in the club.
Split into simpler sentences: The Sydney Cup is an Australian Turf Club Group 1 horse race, held for Thoroughbred horses and run over 3200 metres. It is run every year at Randwick Racecourse in Sydney, New South Wales during the Autumn Carnival and it is the longest race in the club.