zài / nà / duàn / lì / shǐ / zhōng / fǎn / dòng / fèn / zǐ / céng / shì / tú / zǔ / zhǐ / shè / huì / gǎi / gé

在那段历史中，反动分子曾试图阻止社会改革。

During that period of history, reactionary elements attempted to stop social reform.