classification of income by character

例句：

1. 1. The scientists classified the new species into different groups.
   科学家们将新物种分为不同的组。
2. 2. The teacher asked us to classify the books by topic.
   老师让我们根据主题把书分类。
3. 3. The researchers classified the data according to their findings.
   研究人员根据他们的发现对数据进行了分类。