 Complete the following phrase:  On 19 June 39th Siege Bty was back in action north of Arras. 30th Brigade was now under First Army and remained with it until the end of the war. The summer was spent on HF and counter-battery CB fire tasks. The Allied Hundred Days Offensive began on 8 August and First Army began to advance on 18 August, supported by CB fire. On 19 September the heavy guns began moving forward to support First Army in the 