管子板牙套丝时,应使板牙端面与圆管轴线(),以免套出不合规格的螺纹。
A.成45°角
B.垂直
C.水平
D.平行
参考答案:B
—Can you tell me _____?
—Yesterday. [ ]
A. when did he buy the car
B. where did he buy the car
C. when he bought the car
D. where he bought the car
安全管理主要是组织实施企业安全管理(),同时,又是保证生产处于最佳安全状态的根本环节。
A.控制
B.规划
C.指导
D.检查
E.决策