( ( The system ) ( ( uses ( electric ( energy ( to ( light ( the bulb ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN system)) (VP (VBZ uses) (NP (JJ electric) (NN energy) (S (VP (TO to) (VP (VB light) (NP (DT the) (NN bulb))))))) (. .)))
The system uses electric energy to light the bulb.
(ROOT (S (NP (DT A) (JJ light) (NN bulb)) (VP (VBZ converts) (NP (JJ electrical) (NN energy)) (PP (TO to) (NP (JJ light) (CC and) (JJ thermal) (NN energy)))) (. .)))