$re = '/^.{0,2}(你知道)?#有?(什么|啥)(好?(吃的|食物)|((东西|玩意)?好吃))(吗|么|嘛|不)?$/m';
$str = '#有什么好吃的
#有啥好吃的
#啥好吃
#什么玩意好吃
#啥东西好吃
去#吃啥
到#吃什么好吃的
去#应该吃啥';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php