( ( Both ( mechanical ( digestion ( and ( chemical digestion ) ) ) ) ) ( ( begin ( in ( the mouth ) ) ) . ) )
(ROOT (S (NP (DT Both) (JJ mechanical) (NN digestion) (CC and) (NN chemical) (NN digestion)) (VP (VBP begin) (PP (IN in) (NP (DT the) (NN mouth)))) (. .)))
Both mechanical digestion and chemical digestion begin in the mouth.
(ROOT (S (NP (NNP Digestion)) (VP (VBZ begins) (PP (IN in) (NP (DT the) (NN mouth)))) (. .)))