Complex sentence: Returning to Australia in 1990, Sheil accepted a lectureship in chemistry at the University of Wollongong, was promoted to Professor of Chemistry in 2000 before becoming Dean of Science in 2001.
Split into simpler sentences: Returning to Australia in 1990, Sheil accepted a lectureship in chemistry at the University of Wollongong. Margaret was promoted to Professor of Chemistry in 2000 before becoming Dean of Science in 2001.