要获取最新评论，请使用get_comments().
get_comment_date 返回任何格式的注释的日期，以供PHP使用date().

现在很容易了。让我们将逻辑放入一个函数中，以保持全局命名空间干净：

/**
 * Returns the number of days since the latest comment.
 *
 * @return int
 */
function get_days_since_last_comment( $post_id = 0 )
{
    $args = array (
            \'number\' => 1,
            \'status\' => \'approve\'
        );
    0 !== $post_id and $args[\'post_id\'] = (int) $post_id;
    // Array of comment objects.
    $latest_comment = get_comments( $args );

    // No comments found.
    if ( ! $latest_comment )
    {
        return -1;
    }

    $comment_unix = get_comment_date( \'U\', $latest_comment[0]->comment_ID );
    return round( ( time() - $comment_unix ) / 86400 );
}

要显示特殊消息，请执行以下操作：

if ( get_days_since_last_comment() > 7 )
{
    print \'Looks like everything has been said.\';
}

if ( get_days_since_last_comment( 123 ) > 7 )
{
    print \'Looks like everything has been said.\';
}