变频器总是把直流电能变换成50Hz交流电能。（）

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku where sourceid='32684' and id < 2599730 and id<>'2599730' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='32684' and id > 2599730 and id<>'2599730' order by id asc limit 5