ephemeral [active] region

例句：

1. 1.The sun's rays are a reminder of the ephemeral nature of life.
   太阳的光芒提醒我们生命的短暂。
2. 2.The ephemeral beauty of the sunset is often overlooked by those who live in cities.
   夕阳的美丽是短暂的，常常被城市里的人忽略。
3. 3.The ephemeral joy of a new beginning can be hard to find amidst the chaos of daily life.
   在日常生活的混乱中，新开始带来的短暂快乐很难找到。