Complex sentence: Determine, a soft gray in color, grew to a little over fifteen hands and never weighed more than 900 pounds, but in his two-year-old season he won double his purchase price.
Split into simpler sentences: Determine, a soft gray in color, grew to a little over fifteen hands and never weighed more than 900 pounds. In his two-year-old season Determine won prize money which totaled more than double his purchase price.