sentence2_structure: earth's shadow<>falls<>on the moon$$$the shadow<>causes<>a lunar eclipse<>When earth's shadow falls on the moon
sentence1: Eclipses occur when the Earth, Sun, and Moon lie along a line such that either the shadow of the Earth falls on the Moon (lunar eclipse) or the Moon's shadow falls on the Earth (solar eclipse).
sentence2: When earth’s shadow falls on the moon, the shadow causes a lunar eclipse.
question: When Earth’s shadow falls on the Moon, the shadow causes a