读Carhart(1997)那篇论文,看到里面构建momentum因子的一句话, I construct PR1YR as the equal-weight average of firms with the highest 30 percent eleven-month returns lagged one month minus the equal-weight average of firms with the lowest 30 percent eleven-month returns lagged one month. 没有看懂,麻烦大牛指点啊