.两个(   )正弦量之间的相位之差称为相位差（  ）频率的正弦量之间不存在相位差的概念。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69455' and id < 4498031 and id<>'4498031' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69455' and id > 4498031 and id<>'4498031' order by id asc limit 5