Complex sentence: Benito Mussolini tried to keep races going during the war but the Giro used so much gasoline, food and other supplies that it would hurt Italy's war effort, so the government created a competition based on one-day races.
Split into simpler sentences: Benito Mussolini tried to keep races going during the war. But the Giro used so much gasoline, food and other supplies that it would hurt Italy's war effort, so the government created a competition based on one-day races.