Complex sentence: Opened on July 18,2009, Central Link initially operated between downtown Seattle and Tukwila, on a route, but service was extended by from Tukwila to SeaTac Airport on December 19,2009.
Split into simpler sentences: Opened on July 18,2009, Central Link initially operated between downtown Seattle and Tukwila, on a route. Service was extended by from Tukwila to SeaTac Airport on December 19,2009.