( ( The ( small intestine ) ) ( ( is ( ( the ( main site ) ) ( of ( both ( digestion ( and ( nutrient absorption ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ small) (NN intestine)) (VP (VBZ is) (NP (NP (DT the) (JJ main) (NN site)) (PP (IN of) (NP (DT both) (NN digestion) (CC and) (NN nutrient) (NN absorption))))) (. .)))
The small intestine is the main site of both digestion and nutrient absorption.
(ROOT (S (NP (NNP Chemical) (NNP digestion)) (ADVP (RB mainly)) (VP (VBZ occurs) (PP (IN in) (NP (DT the) (JJ small) (NN intestine)))) (. .)))