grade up

• • 挑选，分等级：

    The apples were graded up before being sent to market.

    苹果在上市前被分了等级。

  • 升级，升等：

    All students in this class will be graded up.

    这个班的所有学生都将升级。

  • 【畜牧业】(把杂种、劣种动物)与纯种杂交改良：

    He graded up his herd.

    他使他的牛与良种牛交配。