Understanding animating on group

Understanding animating on group

Hi all,

If i'm doing this :

$(".abc").animate({
        top     : '40px',
        left    : '40px',
        opacity : "show",
        width   : 400,
        height  : 300
         }, 1000, null, null);


and that my $(".abc") returns many elements, all elements animate at the same time.

How can I do to have the elements animate each one after the other ?

Thanks for your help