额定电压为1kV及以下的中性点接地系统中的用电设备应采用（）。
A.保护接地
B.工作接地
C.保护接零
D.重复接地
参考答案：C
自从搬到一个新城市后，我一直想念过去的老朋友。
A．深
B．很
C．好
D．旧
―That actor often joins in different activities in Beijing. Do you know ?
―For 5 years.[ ]
A. how soon he will come back
B. how long he has stayed there
C. when he went there
D. when he will come here
