More and more people are signing up for Yoga classes nowadays, ______ advantage of the health

and relaxation benefits.[ ]

A. taking

B. taken

C. having taken

D. having been taken

磨削加工中所用砂轮的三个基本组成要素是（）。

A、磨料、结合剂、孔隙

B、磨料、结合剂、硬度

C、磨料、硬度、孔隙

D、硬度、颗粒度、孔隙