 Complete the following phrase:  After completing flying training, Gardner was assigned to No. 19 Squadron RFC in January 1918, flying the Sopwith Dolphin. On 1 April 1918, the Royal Flying Corps and the Royal Naval Air Service merged to create the Royal Air Force. Gardners first victory came on 6 June 1918 during the German spring offensive, that had begun in March, pushing the British back over all of the ground they had gained since the Battle of the Somme in 1916, bringing down a DFW C.V over Vieux-Berquin. It was shared with three other pilots, Gordon Budd Irving, Finlay McQuistan, and John De Pencier. Three days later, on 9 June, he destroyed another DFW C.V solo over Neuf-Berquin. In July, he brought down a further four enemy aircraft. 8 August saw the start of the 