Complex sentence: The Republic of China's National Revolutionary Army has only one mechanized division during early stages of the war, the 200th Division, which used pre-WWII tanks acquired from Italy, Germany, and the Soviet Union.
Split into simpler sentences: The Republic of China's National Revolutionary Army's 200th Division was the country's only mechanized division during the war. The 200th used pre-war tanks acquired from Italy, Germany, and the Soviet Union.