UPS电源主机定期维护的主要内容是（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='29462' and id < 2399389 and id<>'2399389' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='29462' and id > 2399389 and id<>'2399389' order by id asc limit 5