 Complete the following phrase:  After Fromelles, the 57th spent the next two-and-a-half years in the trenches in France and Belgium, seeing action in many of the major battles fought by the Australians during this time. In 1917, the battalion joined the brief advance that the Allies undertook when the Germans withdrew to the Hindenburg Line. It then undertook a defensive role during the Second Battle of Bullecourt, before mounting a major attack at Polygon Wood in September after the 5th Division was transferred to the Ypres sector in Belgium. The following year, the Germans launched a major offensive on the Western Front after the collapse of Tsarist Russia. The 57th Battalion undertook a defensive role around Corbie, before participating in a counter-attack on the morning of 25 April 1918Anzac Dayat Villers-Bretonneux. In July, the 60th took part in a diversionary attack around the Ancre River, during the Battle of Hamel. In August, the 57th joined the Allied 