The price of nails fell by 90% between the late 1700s and mid-1900s, as economist Daniel Sichel points out in a research paper.
如经济学家丹尼尔·西格尔在一篇研究论文中所指出的那样，钉子的价格在18世纪末到19世纪中期之间下降了90%。
According to Sichel, although the falling price of nails was driven partly by cheaper iron and cheaper energy, most of the credit goes to nail manufacturers who simply found more efficient ways to turn steel into nails.
根据西格尔的说法，尽管钉子价格的下降部分是由于铁和能源成本的降低，但大部分功劳应归于钉子制造商，他们只是找到了更有效的方法将钢转化为钉子。
Nails themselves have changed over the years, but Sichel studied them because they haven't changed much.
钉子本身在这些年里已经发生了变化，但西格尔研究它们是因为钉子的变化不大。
例句取自历年考研英语真题，翻译为机器生成，仅供学习参考。