设备通用维护作业计划中日常维护要求有人站机房设备运行状况巡视的维护周期()
A.1次/天
B.2次/天
C.3次/天
D.5次/天
参考答案:C
David's parents _____________ for a walk in the park last night. [ ]
A. went
B. goes
C. go
二次设备