Complex sentence: Helga's intelligent, outgoing, beautiful older sister, who attends the fictional Wellington College, although in one episode, Helga says that Olga attends Bennington College, which is an existing college located in the U.S. state of Vermont.
Split into simpler sentences: Helga's intelligent, outgoing, beautiful older sister, who attends the fictional Wellington College. But in one of the episodes, Helga says that Olga attends Bennington College, which is an existing college located in the U.S. state of Vermont.