关于php承袭的疑惑

关于php继承的疑惑

PHP code

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<?php class A {
    [color=#FF0000]private[/color] $name = "Nciaer";

    public function say() {
        echo $this -> name . "<br>";
    }
}

class B extends A {
    public $name = "Fansa";

}

$b = new B();
$b -> say();
?>

输出结果：
Nciaer
----------------------------

PHP code

<!--

Code highlighting produced by Actipro CodeHighlighter (freeware)
http://www.CodeHighlighter.com/

-->
<?php class A {
    [color=#FF0000]public[/color] $name = "Nciaer";

    public function say() {
        echo $this -> name . "<br>";
    }
}

class B extends A {
    public $name = "Fansa";

}

$b = new B();
$b -> say();
?>

输出结果：
Fansa


为什么父类变量$name为public的时候，$b调用成员方法say()输出子类的$name;
当父类变量$name为private时，$b调用成员方法say()输出父类的$name;

------解决方案--------------------
private 私有的
怎么能被继承呢？