Complex sentence: The 1974 report of the German archives estimated 60,000 German civilians died in Polish communist camps and 40,0000 in Soviet detention in Poland, not including 100,000 killed by the Red Army and their Allies during the war and 200,000 in forced labor in the USSR.
Split into simpler sentences: The 1974 Report of the German archives estimated 60,000 German civilians died in Polish communist camps and 40,0000 in Soviet detention in Poland. Not including 100,000 killed by the Red army and their Allies during the war and 200,000 in forced labor in the USSR.