( ( A decibel ) ( ( is ( ( a unit ) ( of ( sound intensity ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN decibel)) (VP (VBZ is) (NP (NP (DT a) (NN unit)) (PP (IN of) (NP (JJ sound) (NN intensity))))) (. .)))
A decibel is a unit of sound intensity.
(ROOT (S (NP (NNP Decibel)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (VP (VBN used) (S (VP (TO to) (VP (VB measure) (NP (NP (DT the) (NN intensity)) (PP (IN of) (NP (JJ sound) (NNS waves)))))))))) (. .)))