怎么出现的是这个结果

Notice: Use of undefined constant echo__FILE__ - assumed 'echo__FILE__' in /54/806/GR8i/index.php on line 2 Notice: Use of undefined constant echo__LINE__ - assumed 'echo__LINE__' in /54/806/GR8i/index.php on line 4 5.6.11 Linux 怎么回事啊，我明明两边都用了两条下划线