问当类继承类时，方法重写是如何工作的？

EN

class Bar 
{
    public function test() {
        echo "<br>";
        $this->testPrivate();
        $this->testPublic();
    }

    public function testPublic() {
        echo "Bar::testPublicn";
    }

    private function testPrivate() {
        echo "Bar::testPrivaten";
    }

    public function ShowBar() {
        $this->testPrivate();
    }
}

class Foo extends Bar 
{
    public function testPublic() {
        echo "Foo::testPublicn";
    }

    private function testPrivate() {
        echo "Foo::testPrivaten";
    }

    public function ShowFoo() {
        $this->testPrivate();
    }
} 
$myFoo = new Foo();
$myFoo->test();

echo "<br>"; 
$myFoo->ShowBar();

echo "<br>"; 
$myFoo->ShowFoo();