目前自然界中已知硬度最高的物质是金刚石。（ ）

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SQL Error: select id,body,options from ***_enewstiku where sourceid='27190' and id < 2254516 and id<>'2254516' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='27190' and id > 2254516 and id<>'2254516' order by id asc limit 5