Complex sentence: After a six-day halt for preparations and artillery bombardments Fourth Army troops attacked at 5.20am on Thursday 17 October; infantry and tanks, preceded by a creeping barrage, moved forward on a ten mile wide front south of Le Cateau.
Split into simpler sentences: After a six-day halt for preparations and artillery bombardments Fourth Army troops attacked at 5.20 a.m. on Thursday 17 October. Infantry and tanks, preceded by a creeping barrage, moved forward on a front south of Le Cateau.