trading up短语⁶⁷⁸⁴¹ 基本例句 升格销售,经营高档商品提高利润率 Trading up yields the most improvement in a diamond's value. 它能够在很大程度上提升钻石的价值。 yeeyan The best students would go to the UC, the next lot to Cal State and the rest to community colleges with the possibility of trading up. 最优秀的学生将进入加州大学学习，而进入加州州立大学的第二层次和剩余的进入社区大学的第三层次学生也有机会升级转学到更高层次的学府学习。 ecocn