Complex sentence: The family was forced to move in with Josephine's older sister Sophia and her husband in the flatlands "south of the slot" (south of Market Street), a working class, ethnically mixed neighborhood, where smoke from factory chimneys filled the air.
Split into simpler sentences: The family was forced to move in with Josephine's older sister Sophia and her husband in the flatlands south of Market Street. It was known as "the slot," a working class, ethnically mixed neighborhood, where smoke from factory chimneys filled the air.