wordpress 如何让文章时间显示为多少天几周几月几年前？

function format_date($time)
{
    global $options, $post;
    $p_id = isset($post->ID) ? $post->ID : 0;
    $q_id = get_queried_object_id();
    $single = $p_id == $q_id && is_single();
    if (isset($options['time_format']) && $options['time_format'] == '0') {
        return date(get_option('date_format') . ($single ? ' ' . get_option('time_format') : ''), $time);
    }
    $t = current_time('timestamp') - $time;
    $f = array(
        '86400' => '天',
        '3600' => '小时',
        '60' => '分钟',
        '1' => '秒'
    );
    if ($t == 0) {
        return '1秒前';
    } else if ($t >= 604800 || $t < 0) {
        return date(get_option('date_format') . ($single ? ' ' . get_option('time_format') : ''), $time);
    } else {
        foreach ($f as $k => $v) {
            if (0 != $c = floor($t / (int)$k)) {
                return $c . $v . '前';
            }
        }
    }
}
add_filter('the_time','format_date');