( ( ( ( lunar eclipse ) -- ) ( ( the passage ) ( of ( ( ( ( the Moon ) ( into ( ( the shadow ) ( of ( the Earth ) ) ) ) ) , ) ( always ( occurring ( at ( a ( full Moon ) ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NN lunar) (NN eclipse)) (: --) (NP (NP (DT the) (NN passage)) (PP (IN of) (NP (NP (DT the) (NN Moon)) (PP (IN into) (NP (NP (DT the) (NN shadow)) (PP (IN of) (NP (DT the) (NN Earth))))) (, ,) (VP (ADVP (RB always)) (VBG occurring) (PP (IN at) (NP (DT a) (JJ full) (NN Moon))))))) (. .)))
lunar eclipse -- the passage of the Moon into the shadow of the Earth, always occurring at a full Moon.
(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.