2 sentences

1. 这些书籍是按题材区分为不同类别的。

   zhè​xiē shū​jí shì àn tí​cái qū​fēn wéi bù​tóng lèi​bié de.

   These books are categorized into different classes based on their subject matter.

   Source: Dong Chinese Dictionary

2. 这些书籍按内容类别分放在不同的书架上。

   zhè​xiē shū​jí àn nèi​róng lèi​bié fēn fàng zài bù​tóng de shū​jià shàng.

   These books are arranged on different shelves according to their content categories.

   Source: Dong Chinese Dictionary