在潮湿和易触及带电体的场所作业电源电压不得大于24V。
参考答案：对
解析：在潮湿和易触及带电体的场所作业电源电压不得大于24V。
Only when he returned______ the truth.
A．he found out
B．did he find out
C．he finds out
D．does he find out
单项选择。
Flying is birds. [ ]
A. for
B. to
C. on
D. with
