category of functors

例句：

1. 1. Different categories of animalsare found in the forest.
   森林里有不同的动物种类。
2. 2. The teacher asked us to categorize the fruits by color.
   老师让我们根据颜色将水果进行分类。
3. 3. This bookis divided into several categories for easy reference.
   这本书被分成几个类别以便容易参考。