Complex sentence: The 39th Division regiments managed a slow advance, behind showers of hand grenades and trench mortar fire but were forced back when the left-hand regiment was repulsed; the 11th Division was bogged down in Neuville and "the Labyrynth".
Split into simpler sentences: The 39th Division advanced, the infantry moving behind a shower of hand grenades and trench mortar bombs but was forced back when the left-hand regiment was repulsed. The 11th Division was bogged down in Neuville and "the Labyrynth".