双圆弧滚珠螺纹丝杠的螺距误差按误差特性分为3种:()。
A、局部性误差;
B、工件的定位夹紧误差;
C、周期性误差;
D、渐进性误差;
参考答案:A, C, D
The ancient Jewish people regarded themselves as the salt of the earth, the chosen few by God to rule the world.
A.outcast
B.elite
C.nomad
D.disciple
对于加工、运输、储存可燃性气体的设备检修,必须经置换分析合格后才能进行检修。