( ( ( ( ( ( ( Carbohydrates and ) fats ) ( are ( ( the ( major sources ) ) ( of ( energy ( in ( our diets ) ) ) ) ) ) ) ( , ( ( Proteins ( also ( contribute energy ) ) ) , ) ) ) but ) ( ( their ( ( more important ) role ) ) ( is ( to ( ( provide ( amino acids ) ) ( ( ( to ( ( promote growth ) ( -LRB- ( ( in children ) -RRB- ) ) ) ) and ) ( to ( repair ( body tissues ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNS Carbohydrates) (CC and) (NNS fats)) (VP (VBP are) (NP (NP (DT the) (JJ major) (NNS sources)) (PP (IN of) (NP (NP (NN energy)) (PP (IN in) (NP (PRP$ our) (NNS diets)))))))) (PRN (, ,) (S (NP (NNPS Proteins)) (VP (ADVP (RB also)) (VBP contribute) (NP (NN energy)))) (, ,)) (CC but) (S (NP (PRP$ their) (ADJP (RBR more) (JJ important)) (NN role)) (VP (VBZ is) (S (VP (TO to) (VP (VB provide) (NP (JJ amino) (NNS acids)) (S (VP (VP (TO to) (VP (VB promote) (NP (NN growth)) (PRN (-LRB- -LRB-) (PP (IN in) (NP (NNS children))) (-RRB- -RRB-)))) (CC and) (VP (TO to) (VP (VB repair) (NP (NN body) (NNS tissues))))))))))) (. .)))
Carbohydrates and fats are the major sources of energy in our diets, Proteins also contribute energy, but their more important role is to provide amino acids to promote growth (in children) and to repair body tissues.
(ROOT (S (NP (NNP Protein)) (VP (VBZ is) (NP (NP (DT an) (JJ important) (NN part)) (PP (IN of) (NP (DT a) (JJ healthy) (NN diet)))) (SBAR (IN because) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN needed) (S (VP (TO to) (VP (VB repair) (NP (NN tissue)))))))))) (. .)))