人体组织声衰减的主要因素是（     ）

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku where sourceid='25744' and id < 2163585 and id<>'2163585' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='25744' and id > 2163585 and id<>'2163585' order by id asc limit 5