( ( ( A shadow ) ( cast ( by ( ( the Earth ) ( on ( the Moon ) ) ) ) ) ) ( ( is ( a ( lunar eclipse ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NN shadow)) (VP (VBN cast) (PP (IN by) (NP (NP (DT the) (NN Earth)) (PP (IN on) (NP (DT the) (NNP Moon))))))) (VP (VBZ is) (NP (DT a) (NN lunar) (NN eclipse))) (. .)))
A shadow cast by the Earth on the Moon is a lunar eclipse.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NP (NN earth) (POS 's)) (NN shadow)) (VP (VBZ falls) (PP (IN on) (NP (DT the) (NN moon)))))) (, ,) (NP (DT the) (NN shadow)) (VP (VBZ causes) (NP (DT a) (NN lunar) (NN eclipse))) (. .)))
When earth’s shadow falls on the moon, the shadow causes a lunar eclipse.