通过注册页面对象类型的类别分类法，可以将类别用于页面：

function categories_for_pages(){
    register_taxonomy_for_object_type( \'category\', \'page\' );
}
add_action( \'init\', \'categories_for_pages\' );

1. First thing you need to do is to enable categories for pages, quite simple:

   function enable_categories_for_pages() {
       register_taxonomy_for_object_type(\'category\', \'page\');  
   }
   add_action( \'init\', \'enable_categories_for_pages\' );
   

Note that in WordPress, categories are shared between different post types

1. To register the categories in advance:

   $wp_insert_category(array(
       \'cat_name\' => \'Fruit\',
       \'category_description\' => \'My Fruit posts\',
       \'category_nicename\' => \'Fruit\'
   ));
   

2. You can add categories to posts programmatically:

   wp_set_post_categories($post->ID, get_cat_ID( \'Fruit\' ));
   

3. When displaying the page （以Wordpress$post命名）：

   if ($post->post_type == \'page\'){
       if (has_category( \'Fruits\', $post)){
           echo "This is related to Fruits.";
       }
   }