hi, i have some problems adding query_vars

[ Moderator note: Fixed, please do not use all caps when posting. It’s considered to be rude. ]

i registerd a query_var correctly using the following code:
function add_my_query_var($vars) {

$vars[] = ‘my_var’;
return $vars;
}

add_filter(‘query_vars’, ‘add_my_query_var’);

how should that be changed to add multiple query_vars?