对称三相正弦量的一个特点是，它们的任一瞬间的和不为零。(     )

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='68473' and id < 4421045 and id<>'4421045' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='68473' and id > 4421045 and id<>'4421045' order by id asc limit 5