Complex sentence: During the second world war, Paul Janssen studied physics, biology, and chemistry at the Faculté Notre Dame de la Paix in Namur after which he studied medicine at the Catholic University of Leuven and the University of Ghent.
Split into simpler sentences: During the second world war, Paul Janssen studied physics, biology, and chemistry at the Faculté Notre Dame de la Paix in Namur. He then studied medicine at the Catholic University of Leuven and the University of Ghent.