<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.html$ /index\.php
RewriteRule ^html/([a-z0-9A-Z]+)_([0-9]+)\.html$ $1\.php\?class_id=$2
RewriteRule ^html/([a-z0-9A-Z]+)_([0-9]+)_([0-9]+)\.html$ $1\.php\?class_id=$2&page=$3
RewriteRule ^html/([a-z0-9A-Z]+)_content_([0-9]+)\.html$ $1_content\.php\?$1_id=$2
</IfModule>