yán / jiū / rén / yuán / yòng / bù / biàn / jià / gé / bǐ / jiào / le / bù / tóng / nián / fèn / de / jīng / jì / shù / jù研究人员用不变价格比较了不同年份的经济数据。Researchers compared economic data from different years using constant prices.