Complex sentence: The middle school was added in 1995 and the high school in 1998.in 2011, a large portion of the student body was infected with E. coli and were seen in the hospital for many weeks afterward.
Split into simpler sentences: The middle school was added in 1995 and the high school in 1998. In 2011, a large portion of the student body was infected with E. coli and were seen in the hospital for many weeks afterward.