Complex sentence: O'Connor attended St Mary's Grammar School, Bootle and Saint Mary's College, Twickenham and was then a mathematics and music teacher at the St Joan Of Arc School, Bootle.
Split into simpler sentences: O'Connor attended St. Mary's Grammar School, Bootle and Saint Mary's College, Twickenham. He became a mathematics and music teacher at the St Joan Of Arc School, Bootle.