My birthday is on ____. [ ]
A. July twenty fifth
B. June one
C. August first
答案:C
过滤介质的选择,应从()方面进行考虑。
A.2个
B.3个
C.4个
D.5个
检定人员在评定计量特性前,必须先对计量器具的外观、工作正常性等非计量特性进行检查。()