Complex sentence: The New York Handicap (also known as the New York Breeders' Cup Handicap) is a race for thoroughbred horses open to fillies and mares, age three and up, willing to race one and one-quarter miles on the Belmont Park turf.
Split into simpler sentences: The New York Handicap (also known as the New York Breeders' Cup Handicap) is a race for thoroughbred horses. The race is open to fillies and mares age three and up willing to race one and one-quarter miles on the Belmont Park turf.