Complex sentence: Clarke's football team also beat the number two seed in the county in the playoffs to become the Big-4 champs in 2009, they were also 1997 Nassau County Champions and Long Island Finalist.
Split into simpler sentences: Clarke's football team also beat the number two seed in the county in the playoffs to become the Big-4 champs in 2009. They were also 1997 Nassau County Champions and Long Island Finalist.