滚动导靴的三个滚轮在弹簧力的作用下,压贴在导轨的两个工作面上()
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对某市工程技术人员进行普查,该市工程技术人员的工资收入水平是数量标志。(√)
A. 正确
B. 错误
按经营主体不同,可将批发商业分为()、制造批发商、()、批兼零批发商、连锁批发商和商品代理商。
《钢质无缝气瓶定期检验与评定》(GB/T13004-2016)7.1.1规定,用直接目测或借助低倍放大镜目测检查气瓶时,应逐只检查瓶口螺纹有无()、腐蚀或其他机械损伤。
A. 锈迹
B. 裂纹
C. 变形
D. 磨损
Which of the following statements is correct with regards to the operation of a centrifugal cargo pump?()
A. Oil is discharged from the impeller through the outlet
B. Gravity causes the oil to flow toward the discharge
C. The self-priming feature of the centrifugal pump enables it to draw its own suction as it starts
D. The discharge capacity varies directly with the speed of the impeller