已知电压V，则其有效值。

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='68466' and id < 4420860 and id<>'4420860' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='68466' and id > 4420860 and id<>'4420860' order by id asc limit 5