arrays - PHP: suddenly can't parse some word

$team = trim(split("are", $string)[0]); // Line 215

this code has syntax error but i can't solve this :(

Parse error: syntax error, unexpected '[' in /home/zz.php on line 215

and When I define varible like this

$array = [
      "a",
      "b",
];

Parse error: syntax error, unexpected '['

too