设a，b，c，d都是非零实数，则四个数:-ab，ac，bd，cd(  ).

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SQL Error: select id,body,options from ***_enewstiku where sourceid='27159' and id < 2250212 and id<>'2250212' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='27159' and id > 2250212 and id<>'2250212' order by id asc limit 5