external classification

例句：

1. 1. The company has adopted an external classification system for its products.
   该公司已为其产品采用了外部分类系统。
2. 2.In the field of economics, external classification is crucial for understanding market dynamics.
   在经济学领域，外部分类对于理解市场动态至关重要。
3. 3.The new tax law introduces a more sophisticated external classification system to simplify the process.
   新税法引入了更复杂的外部分类系统，以简化流程。