first contact of umbra

例句：

1. 1. The umbra of the moon casts a long shadow on the ground.
   月亮的阴影在地面上投下了长长的影子。
2. 2. The umbra of the forest is so deep that it's almost invisible.
   森林的阴影如此之深，几乎看不见。
3. 3. The umbra of the city obscured the view of the distant mountains.
   城市的阴影遮蔽了远处山脉的视线。