<?phpclass Person {  var $name;//protected  var $sex;  var $age;  function __construct($name = "", $sex = "男", $age = 22) {    $this->name = $name;    $this->sex = $sex;    $this->age = $age;  }  function say() {    echo $this->name . "在說話<br/>";  }  function run() {    echo "在走路·<br/>";  }}class Student extends Person {  var $school;  function __construct($name = "", $sex = "男", $age = 22,$school="") {    parent::__construct($name,$sex,$age);    $this->school = $school;  }  function study() {    echo $this->name."正在".$this->school."學習<br/>";  }}class Teacher extends Student {  var $wage;  function teaching() {    echo $this->name."正在".$this->school."教學，每月工資為".$this->wage."<br/>";  }}$teacher1 = new Teacher("kaifu","男",22);$teacher1->school = "edu";$teacher1->wage = 4000;$teacher1->say();$teacher1->study();$teacher1->teaching();?>

kaifu在說話kaifu正在edu學習kaifu正在edu教學，每月工資為4000