( ( The ( light energy ) ) ( ( ( boosts ( the electrons ) ) ( into ( higher ( energy levels ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ light) (NN energy)) (VP (VBZ boosts) (NP (DT the) (NNS electrons)) (PP (IN into) (NP (JJR higher) (NN energy) (NNS levels)))) (. .)))
The light energy boosts the electrons into higher energy levels.
(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))))))) (. .)))