size grader的意思|示意

Oh, and I'm doing it all with nothing but a backpack the size of one an eighth grader might use.

我随身只带了一个也许只有八年级学生大小的背包就完成了所有这一切。

This paper analyzed the structure and the working process of three-layer-cylindrical grader and the grading performance and screen mesh-size are experimentally studied.

分析了三层滚筒式银杏分级机的结构特点及工作过程，并对分级机的分级性能及筛孔大小进行了试验研究。