regression of the node

例句：

1. 1. The population has been experiencing a significant decline in recent years.
   近年来，人口出现了显著的下降。
2. 2. The company's stock price has been experiencing a slow but steady regression since the market downturn.
   自市场下跌以来，公司股价一直缓慢但稳定地下滑。
3. 3. The research suggests that the rate of regression may be influenced by external factors.
   研究表明，回归率可能受到外部因素的影响。