促进小肠对钙的吸收的主要因素是（ ）。

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku where sourceid='31197' and id < 2506858 and id<>'2506858' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='31197' and id > 2506858 and id<>'2506858' order by id asc limit 5