Complex sentence: Being primarily an island, Manhattan is linked to New York City's outer boroughs by numerous bridges, large and smaller; while the George Washington Bridge, the world's busiest motor vehicle bridge, connects Washington Heights in Upper Manhattan to Bergen County in New Jersey.
Split into simpler sentences: Being primarily an island, Manhattan is linked to New York City's outer boroughs by numerous bridges, large and smaller. The George Washington Bridge, the world's busiest motor vehicle bridge, connects Washington Heights in Upper Manhattan to Bergen County in New Jersey.