引用phprequire once 目录结构是这样的: 1.php 3.php 文件夹2 2.php1.php中require_once 2和3文件2.php中又require_once 3.php报错Fatal error: require_once(): Failed opening required '../3.php'当2.php放置在与13同一目录下则不会出错不懂这是怎么回事?