IoC 容器的问题

看了本网站的一些优秀文章自己实践了一下遇到的疑惑

代码块

<?php
interface Boards {
    public function type();
}

class CommonBoard implements Boards {
    public $test = 233;
    public function type(){
        echo '普通键盘';
    }
}
class MechanicalKeyboard implements Boards {
    public function type(){
        echo '机械键盘';
    }
}

class Computer {
    protected $keyboard;

    public function __construct (Boards $keyboard) {
        $this->keyboard = $keyboard;
    }
}

class Container
{
    protected $binds;

    protected $instances;

    public function bind($abstract, $concrete)
    {
        if ($concrete instanceof Closure) {
            $this->binds[$abstract] = $concrete;
        } else {
            $this->instances[$abstract] = $concrete;
        }
    }

    public function make($abstract, $parameters = [])
    {
        if (isset($this->instances[$abstract])) {
            return $this->instances[$abstract];
        }
        array_unshift($parameters, $this);
        return call_user_func_array($this->binds[$abstract], $parameters);
    }
}

$container = new Container;
$container->bind('Board', function($container){
    return new CommonBoard;
});
$module = new CommonBoard();
$container->bind('Computer',function($container,$module){
    return new Computer($container->make($module));
});

$computer = $container->make('Computer',['Board']);
die(var_dump($computer));

疑问

1. 上述代码最后$computer = $container->make('Computer',['Board'])中make方法第二个参数不是为什么只传了一个Board数组，最后打印出CommonBoard对象，?