Complex sentence: The Calgary Highlanders attacked Loon-Plage on 7 September against very heavy opposition and suffered heavy casualties that reduced each of its companies to less than 30 men; the village was gained on the 9th only when the Germans withdrew.
Split into simpler sentences: The Calgary Highlanders attacked Loon-Plage on 7 September against very heavy opposition and suffered enough casualties that each of its companies was reduced to less than 30 men. The village was gained on the 9th only when the Germans withdrew.