Complex sentence: Meanwhile Desert Mounted Corps advanced to capture the communications hubs of Afulah, Beisan and Jenin on 20 September to cut all main lines of retreat by capturing the Ottoman lines of supply and communications.
Split into simpler sentences: Meanwhile Desert Mounted Corps advanced to capture the communications hubs of Afulah, Beisan and Jenin on 20 September. This cut all main lines of the Ottoman retreat by capturing their lines of supply and communications.