常用的齿轮有三种分别是();()和蜗杆齿。
参考答案:圆柱齿轮、圆锥齿轮
—Would you mind ________ my pet dog while I'm not at home?
—Of course not. [ ]
A. looking at
B. looking up
C. looking for
D. looking after
简述员工工作绩效评估的程序。