Options +FollowSymLinks -MultiViews

RewriteEngine On
RewriteRule ^([^/]+)/([^/]+)/([^/]+)/([^/]+) index.php?pet=$1&act=$2&data=$3&data2=$4 [L,QSA]
RewriteRule ^([^/]+)/([^/]+)/([^/]+) index.php?pet=$1&act=$2&data=$3 [L,QSA]
RewriteRule ^([^/]+)/([^/]+) index.php?pet=$1&act=$2 [L,QSA]
RewriteRule ^([^/]+) index.php?pet=$1 [L,QSA]