 Complete the following phrase:  By the beginning of the Meuse-Argonne Offensive the Air Service AEF consisted of 32 squadrons 15 pursuit, 13 observation, and 4 bombing at the front, while by November 11, 1918, 45 squadrons 20 pursuit, 18 observation, and 7 bombardment had been assembled for combat. During the war, these squadrons played important roles in the Battle of Château-Thierry, the 