 #5.
~~~~~
   PHP
~~~~~
 PHP    ,    .        ,         (). :
<?php
//     PHP
//  
//  $primer
$primer = '    $,  $my_variable';
//   
//  
echo $primer;
//  
?>
       : "    $,  $my_variable".  ? -  . .      a  PHP       ,     ..   " ".
 2.
<?php
#     PHP
#  
#  $count
$count = 100;
#   
#  $pages
$pages = 500;
#    
#   
echo "   $count ,    $pages ";
#  
?>
 ?        : "   $100 ,    $500 ". ,       '          : "   $count ,    $pages ".
~~~~~
 ...  .   , 
~~~~~
       (Robin Nixon) "  -   PHP, MySQL  JavaScript (Learning PHP, MySQL, and JavaScript).