Hubble classification

例句：

1. 1. The new classification system is designed to categorize animals based on their physical characteristics.
   新的分类系统旨在根据动物的物理特征进行分类。
2. 2. The astrophysicist used the Hubble classification to study the evolution of galaxies.
   这位天文学家使用哈勃分类研究星系的演变。
3. 3. In this paper, we propose a new classification method based on the Hubble classification.
   在本文中，我们提出了一种基于哈勃分类的新方法。