Complex sentence: Checkers Drive-In Restaurants, Inc., is one of the largest chains of double drive-thru restaurants in the United States specializing in hamburgers, hot dogs, french fries, and milkshakes.
Split into simpler sentences: Checkers Drive-In Restaurants, Inc., is one of the largest chains of double drive-thru restaurants in the United States. They specialize in hamburgers, hot dogs, french fries, and milkshakes.