大神仙，老神仙，不大不小中神仙，给看看呗.为何继承了就没数据值了呢。我啥没理解呢？

<?php$config = array();$config['DB_HOST']='localhost';$config['DB_USER']='root';$config['DB_PASS']='';$config['DB_NAME']='hfdb';foreach($config as $name =>$val){	define($name,$val);}$dsn = "mysql:host=".DB_HOST.";dbname=".DB_NAME;$dbo = new PDO($dsn,DB_USER,DB_PASS);/*$sql="select * from task";$stmt =$dbo->prepare($sql);$stmt ->execute();$results = $stmt -> fetchALL(PDO::FETCH_ASSOC);print_r($results); $stmt ->closeCursor();*/class DB_Connect{	public $db;			protected function __construct($dbo=NULL)	{			$dsn = "mysql:host=".DB_HOST.";dbname=".DB_NAME;			try			{			$this->db =new PDO($dsn,DB_USER,DB_PASS);			}			catch(Exception $e)			{				die($e->getMessage());			}	}}class Task extends DB_Connect{			public function __construct($dbo=NULL,$useData=NULL)	{		parent::__construct($dbo);	}		private function _LoadEventTask ($id=NULL)	{		$sql="SELECT * FROM `task`";		try		{			$stmt = $this->db->prepare($sql);			$stmt ->execute();			$results = $stmt -> fetchALL(PDO::FETCH_ASSOC);			$stmt ->closeCursor();			return $results;		}		catch( Exception $e)		{			die($e->getMessage() );		}	}}$ssss= new Task($dbo);var_dump ($ssss);