Complex sentence: Cesar Chavez Street (formerly Army Street) is the southern border which lies next to Bernal Heights, while to the north the neighborhood is separated from South of Market roughly by Duboce Avenue and the elevated highway of the Central Freeway which runs above 13th Street.
Split into simpler sentences: Cesar Chavez Street (formerly Army Street) is the southern border; across Cesar Chavez Street is the Bernal Heights neighborhood. North of the Mission District is the South of Market neighborhood, bordered roughly by Duboce Avenue and the elevated highway of the Central Freeway which runs above 13th Street.