( Sun ( ( emits ( light energy ) ) . ) )
(ROOT (S (NP (NNP Sun)) (VP (VBZ emits) (NP (JJ light) (NN energy))) (. .)))
Sun emits light energy.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS electrons)) (VP (VB return) (PP (TO to) (NP (DT a) (JJR lower) (NN energy) (NN level)))))) (, ,) (NP (PRP they)) (VP (VBP emit) (NP (NP (DT the) (JJ excess) (NN energy)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (NN light))))))) (. .)))