使用手持照明灯时,电压必须低于()伏。
A.42
B.220
C.380
D.36
参考答案:D
适应于有色金属轴类零件外圆精加工方法是( )
A.磨削
B.精铣
C.拉削
D.精车
When general cargo with different amounts in each draft is involved,the checker must use the ().
A.unit method
B.block method
C.straight method
D.package method