Original sentence: For four years after World War II, both Taiwan and parts of mainland China were governed by the ROC.Taiwan has been controlled by the ROC since 1945.The ROC has controlled only Taiwan and several small islands since 1949, when mainland China was brought completely under control by the Communist Party of China
Edited sentence: For the next 50 year, Taiwan was part of the Empire of Japan.Since 1949, when mainland China was brought completely under control by the Communist Party of China, the ROC has controlled only Taiwan and several small islands.Taiwan came under control by the ROC after the end of World War II in 1945, and for four years, both Taiwan and parts of mainland China were governed by the ROC