如何在登录表单中完成这个rec​​aptcha google

Question

我在php中的recaptcha有问题，如果我可以使用reCAPTCHA PHP客户端库制作小代码，那么提交不起作用

        <?php
       include("db.php");
         session_start();
      require('recap/autoload.php');
        $recaptcha = new \ReCaptcha\ReCaptcha('6LeXoyQUAAAAAIbiIP6-
                 pAx0_wp1G5MYyN7R7wP0');

if($_SERVER["REQUEST_METHOD"] == "POST" ){


$myusername = mysqli_real_escape_string($db,$_POST['username']);
$mypassword = mysqli_real_escape_string($db,$_POST['password']);

$sql = "SELECT id FROM users WHERE username = '$myusername' and passcode = '$mypassword'";
$result = mysqli_query($db,$sql);
$row = mysqli_fetch_array($result,MYSQLI_ASSOC);
$active = $row['active'];
      $resp = $recaptcha->verify($_POST(g-recaptcha-response));
$count = mysqli_num_rows($result);

if($count == 1 && $resp->isSuccess() ) {
   // session_register("myusername");
    $_SESSION['login_user'] = $myusername;

    header("location: welcome.php");
}else {
    $error = "Your Login Name or Password is invalid";
}
      }

     ?>