我假设这是针对帖子的内置类别分类法？这就是这样做的方式。

add_action( \'registered_taxonomy\', \'my_custom_category_paragraph\', 10, 3 );
function my_custom_category_paragraph( $taxonomy, $object_type, $args ) {
    global $wp_taxonomies;
    if ( \'category\' !== $taxonomy )
        return;

    // Change the callback that renders the metabox with our own.
    $wp_taxonomies[$taxonomy]->meta_box_cb = \'my_category_metabox_paragraph\';
}

function my_category_metabox_paragraph( $post, $box ) {
    // add our paragraph here
    echo \'<p>Hi there, sailor!</p>\';
    // Call the default meta box function
    post_categories_meta_box( $post, $box );
}