Complex sentence: After World War II, during the Hungarian Revolution of 1956, Poles demonstrated their support for the Hungarians by donating blood for them; by 12 November 1956,11,196 Poles had donated.
Split into simpler sentences: After World War II, during the Hungarian Revolution of 1956, Poles demonstrated their support for the Hungarians by donating blood for them. By 12 November 1956,11,196 Poles had donated.