当派生类被实例化时，抽象类构造函数是否未被隐式调用?

Take this example:

把这个例子:

abstract class Base {
    function __construct() {
        echo 'Base __construct<br/>';
    }
}

class Child extends Base {
    function __construct() {
        echo 'Child __construct<br/>';
    }
}

$c = new Child();   
abstract class Ba