电能表和互感器应办理()方可报废,报废后不得私自处理或变卖。
A.返库手续
B.审批手续
C.上报手续
D.注销手续
参考答案:B
若x:y:z=2:7:5,且x-2y+3z=6,则x=______,y=______,z=______.
When you are ______, you can come to me for help. [ ]
A. in trouble
B. trouble
C. in dangerous
D. in matter