classification of costs by responsibility

例句：

1. 1. The classification of species is crucial for understanding ecosystems.
   物种的分类对于理解生态系统至关重要。
2. 2. The classifier was designed to help people classify items based on their features.
   分类器被设计用来帮助人们根据特征对物品进行分类。
3. 3. The classification of diseases has become a hot topic in medical research.
   疾病的分类已经成为医学研究中的热门话题。