决定肺部气体交换方向的主要因素是（      ）

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku where sourceid='25939' and id < 2179589 and id<>'2179589' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='25939' and id > 2179589 and id<>'2179589' order by id asc limit 5