brightness decay

例句：

1. 1. The light from the street lamp is fading fast, causing the scene to become darker.
   街灯的光正在迅速变暗，使得整个场景变得更暗。
2. 2.As time passed, the old painting's colors started to fade, losing their vibrant hues.
   随着时间的流逝，这幅旧画的色彩开始褪色，失去了它们鲜艳的颜色。
3. 3. The sun's rays are gradually weakening as the day progresses, leading to a decrease in brightness.
   随着一天的进行，太阳的光线逐渐减弱，导致亮度下降。