Complex sentence: During the German occupation, Dunkirk was largely destroyed by Allied bombings; the artillery siege of Dunkirk was directed on the final day of the war by pilots from No.652 Squadron RAF, and No.665 Squadron RCAF.
Split into simpler sentences: During the German occupation, Dunkirk was largely destroyed by Allied bombings. The artillery siege of Dunkirk was directed on the final day of the war by pilots from No.652 Squadron RAF, and No.665 Squadron RCAF.