( ( The ( digestive process ) ) ( ( begins ( when ( food ( enters ( the mouth ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ digestive) (NN process)) (VP (VBZ begins) (SBAR (WHADVP (WRB when)) (S (NP (NN food)) (VP (VBZ enters) (NP (DT the) (NN mouth)))))) (. .)))
The digestive process begins when food enters the mouth.
(ROOT (S (NP (NNP Digestion)) (VP (VBZ begins) (PP (IN in) (NP (DT the) (NN mouth)))) (. .)))