Complex sentence: The corps artillery was divided into two field artillery groups for each attacking division and the fifth group contained the heaviest artillery, to cover all the corps front, giving one heavy gun for each of front and a field gun for every.
Split into simpler sentences: The corps artillery was divided into two field artillery groups for each attacking division and a fifth group which contained the heaviest artillery, to cover all the corps front. There was one heavy gun for each of front and a field gun for every.