( ( ( One gram ) ( of protein ) ) ( ( provides ( four calories ) ) . ) )
(ROOT (S (NP (NP (CD One) (NN gram)) (PP (IN of) (NP (NN protein)))) (VP (VBZ provides) (NP (CD four) (NNS calories))) (. .)))
One gram of protein provides four calories.
(ROOT (S (NP (NP (CD One) (NN gram)) (PP (IN of) (NP (NNS proteins)))) (VP (VBZ provides) (NP (NP (CD four) (NNS calories)) (PP (IN of) (NP (NN energy))))) (. .)))