变压器效率指输出与输入的有功功率之比（   ）

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69469' and id < 4499024 and id<>'4499024' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69469' and id > 4499024 and id<>'4499024' order by id asc limit 5