Complex sentence: Congestion in the British trenches in front of Trônes Wood made a fresh attack impossible until next day and on 9 August, some battalions had not arrived at zero hour and the attacks failed, British troops isolated in Guillemont being overwhelmed and captured.
Split into simpler sentences: Congestion in the British trenches in front of Trônes Wood, made a fresh attack impossible until next day. On 9 August, some battalions had not arrived by zero hour, the attacks failed and British troops isolated in Guillemont were overwhelmed and captured.