过去田纳西河流域水土流失严重的原因是（      ) ①过度垦殖 　②滥伐森林 ③航运开发 ④经常性的暴雨

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='15823' and id < 1320532 and id<>'1320532' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='15823' and id > 1320532 and id<>'1320532' order by id asc limit 5