暂态地电压局部放电检测仪工作电源：直流电源5V—24V，纹波电压不大于（）。
A.1%
B.2%
C.2.5%
D.3%
参考答案：A
— Who invented _____ cell phone?
— I don't know. Maybe _____ European. [ ]
A. the; an
B. the; a
C. /; /
D. a; the
己知某种好气性细菌的最适生长温度约为37℃，请问如何得知这种细菌在肉汤培养基中培养多少时间就进入平衡期？
