变压器的效率是指变压器的（   ）之比的百分数。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69465' and id < 4499073 and id<>'4499073' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69465' and id > 4499073 and id<>'4499073' order by id asc limit 5