php 测试题

<?php 
   static $num = 3;
   echo $num;exit;
   static $num=5;
?> 
<?php 
   $num = 3;
   echo $num;exit;
   static $num=5;
?> 
<?php 
function myTest(){
   static $num = 3;
   echo $num;exit;
   static $num=5;

  }
myTest();
?> 
<?php 
function myTest(){
    $num = 3;
   echo $num;exit;
   static $num=5;

  }
myTest();
?>