I want to show post time like “___ time ago”

I want to show post time like “___ time ago” as presently its showing time like “_ : _ _ pm/am” How can I do this ?? I tried a lot but not able to do this can I use below function for this :

<abbr title=”<?php echo $t_time ?>”><?php echo apply_filters(‘post_date_column_time’, $h_time, $post, $column_name) ?></abbr>

Plz help me How can I do This.. Waiting for some good reply.