详谈PHP中public,private,protected,abstract等关键字的用法

<?php
abstract class shopping
{
 public function buy()
 {
 echo "buy";
 }
 public function loan()
 {
 echo "loan";
 }
}
class leslieBuy extends shopping
{
}
//$test1=new shopping;//直接语法错误
$leslieSie = new leslieBuy;
$leslieSie->loan();//打印出loan
?>