直流高压试验完毕后,需待试品上的电压降至()试验电压以下,将被试品先经电阻放电,最后直接接地放电。
A.1/2
B.1/3
C.1/4
D.1/5
参考答案:A
— What's the matter with Tom? He seems ____ sad.
— His pet dog died. [ ]
A. feel
B. feels
C. to feel
D. feeling
下列不属于数据的存储和管理的对象是
A.用户数据
B.索引
C.数据字典
D.视图