Her mother is a nurse, sometimes she works _____ night.[ ]
A. in
B. for
C. at
D. during
答案:C
大斌今年a岁,小明今年(a-27)岁,再过3年,他们相差( )
A.3
B.24
C.27
D.30
食品检验、检测机构的设备只要经计量检定合格或校准就可对样品进行检测。