空范畴的英文：
empty category

empty是什么意思：
adj. 空的，空洞的，空虚的
v. 倒空，把…腾出，撤离
n. 空物

The bookshop was empty.
书店里没有人。

The river empties into the ocean .
这条河流入海洋。

He that is full of himself is empty
自满者无知

The theater was half empty.
剧院的座位一半是空着的。

Empties are not taken back.
不退瓶子。

category是什么意思：
n. 种类，分类；范畴

There are different categories of books in a library.
图书馆里有各种不同种类的书籍。

These two categories are aggregated in the tables.
在表中这两大类综合在一起。

The forests are divided into the following five categories
森林分为以下五类

There are two categories of processes based on this concept.
以这一概念为基础的加工工艺有两类。

These Categories recognize different levels of competition.
这些类别可被用来分辨出比赛里不同的等级。