英文を訳して下さい。
The German trenches were on drier ground but barely above water level and parapets and breastworks had been built up, rather than trenches dug. It had proved impossible to build concrete artillery-observation posts, which left the position vulnerable to a surprise attack.
The intended slow build-up of Allied air activity over the Ypres salient was changed to a maximum effort, after a weather delay on 11 July, due to the extent of the opposition of the Luftstreitkräfte. The Germans had been sending larger formations into action and on 12 July, the greatest amount of air activity occurred since the beginning of the war. Thirty German fighters engaged Royal Flying Corps (RFC) and French fighters of the Service Aéronautique in a dogfight lasting an hour, the RFC losing nine aircraft and the Luftstreitkräfte fourteen. The Germans resisted the British and French air effort until the end of July, when their losses forced a change to more defensive tactics. The attack was delayed on 1 July, at the request of Anthoine as the French needed more time to prepare artillery emplacements. On 7 July, Gough asked for another postponement of five days. Some British heavy artillery had been lost to the German counter-bombardment, some had been delayed and bad weather had hampered the programme of counter-battery fire. Haig agreed to delay until the 28 July. Anthoine then requested another delay because the poor weather had slowed his artillery preparation and after Gough supported Anthoine, Haig reluctantly agreed to delay to 31 July, even though this meant postponing Operation Hush from 7–8 August, to the next period of high tides. The first of a series of set-piece attacks was to begin with an advance to three objectives, the blue, black and green lines, through the German front line system and then the Albrecht Stellung (second line) and Wilhelm Stellung (third line), which were approximately 1,000, 2,000 and 3,500 yards (910, 1,830 and 3,200 m) from the British front line, at any of which a halt could be called if necessary.
