Complex sentence: The two longest, Cayuga Lake and Seneca Lake, are among the deepest in America; both are close to 40 miles (64 km) from end to end, and never more than 3.5 miles (5.6 km) wide.
Split into simpler sentences: The two longest, Cayuga Lake and Seneca Lake, are among the deepest in America. Both are close to 40 miles (64 km) from end to end, and never more than 3.5 miles (5.6 km) wide.