$re = '/^.+\sи\s(.+)$/m';
$str = '9 часов назад
1 минута назад
________
день и 9 часов назад
неделю и день назад
3 недели и 3 дня назад
месяц и неделю назад
2 месяца и 3 недели';
$subst = "$1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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