Complex sentence: Preparation of the combined attack became easier after the rain stopped on 30 August; the preliminary bombardment began at on 2 September, from the boundary with the French Sixth Army to High Wood, with a German counter-bombardment mainly falling short on Ginchy.
Split into simpler sentences: Preparation of the combined attack became easier, after the rain stopped on 30 August. The preliminary bombardment began at on 2 September, from the boundary with the French Sixth Army to High Wood, with a German counter-bombardment mainly falling short on Ginchy.