Complex sentence: Now vastly outnumbered the war became a battle of attrition the Germans could not win, as the British were now equipped with new M4 Sherman tanks armed with a 75 mm high velocity gun, making it capable of penetrating the armour of any German vehicle.
Split into simpler sentences: Now vastly outnumbered, the war became a battle of attrition which the Germans could not win. The British were now equipped with new M4 Sherman tanks armed with a 75 mm high velocity gun, making it capable of penetrating the armour of any German vehicle.