Yán / jiū / zhè / duàn / lì / shǐ / shí / tā / chá / yuè / le / Wǔ / dài / shǐ / děng / gǔ / dài / shǐ / shū

研究这段历史时，他查阅了《五代史》等古代史书。

While studying this period of history, he consulted ancient histories such as the History of the Five Dynasties.