超声波是由波源振动而产生，其最低振动 频率不小于

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='31793' and id < 2541698 and id<>'2541698' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='31793' and id > 2541698 and id<>'2541698' order by id asc limit 5