使用兆欧表前不必切断被测设备的电源。
参考答案：对
You shouldn't have the machines _____all the while; you ought to have them _____now and then.[ ]
A run; repair
B. running; repairing
C. run; repaired
D. running; repaired
某大专院校教师情况
该校1997年男女教师的比例为多少
A．2：1
B．2.1：1
C．1.5：1
D．不清楚
