Complex sentence: Leading an advance platoon in the Battle of the Somme in September 1916, he was severely wounded, and spent an entire day lying in a slit trench with a bullet in his pelvis, reading the classical playwright Aeschylus in the original Greek.
Split into simpler sentences: Leading an advance platoon in the Battle of the Somme in September 1916, he was severely wounded. He spent an entire day wounded and lying in a slit trench with a bullet in his pelvis, reading the classical playwright Aeschylus in the original Greek.