重要 joomla二级域名设置 .htaccess要怎么写？

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTP_HOST} ^poll.icaei.org$
RewriteCond %{REQUEST_URI} !^/poll/
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /poll/$1
RewriteCond %{HTTP_HOST} ^poll.icaei.org$
RewriteRule ^(/)?$ poll/ [L]
</IfModule>