机床夹具在机械加工中的作用是什么?
参考答案:
1)保证加工精度;
2)提高劳动生产效率;
3)改善工人的劳动条件;
4)降低生产成材;
5)保证工艺纪律;
6)扩大机床的工艺范围。
Traditional folk arts of Tianjin like paper cutting ________ at the culture show of the 2010 Shanghai
World Expo.[ ]
A. are exhibiting
B. is exhibiting
C. are being exhibited
D. is being exhibited
连轧机的速度调节应该是()。
A.单机架调整
B.级联调节
C.任意调节
D.以上方法均可