变电所操作电源分为( )。
A．直流操作电源
B．高频操作电源
C．交流操作电源
D．控制操作电源
参考答案：A,C
_______ from the operation, the patient was advised to stay in hospital for another two weeks. [ ]
A. Having not fully recovered
B. Being not fully recovered
C. Not having fully recovered
D. Not fully recovering
发放的特种劳动保护用品应具有“三证”，“三证”不包括（）。
A.生产许可证
B.安全许可证
C.安全鉴定证
D.合格证
