轴毛坯有锥度,则粗车后此轴会产生()。
A.圆度误差
B.尺寸误差
C.圆柱度误差
D.位置误差
参考答案:C
三重需要理论中,人们促使别人顺从自己的意志的欲望称为( )。
A.权力需要
B.自我实现需要
C.尊严需要
D.成就需要
There are many kinds of synthetic materials, () plastics are the most common.
A. between which
B. of which
C. in which
D. among which