( ( Once ( food ( enters ( the stomach ) ) ) ) ( , ( it ( ( ( ( begins ( mixing ( with ( digestive juices ) ) ) ) and ) ( is ( ( passed ( into ( the ( small intestine ) ) ) ) ( ( a little ) ( at ( a time ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Once) (S (NP (NN food)) (VP (VBZ enters) (NP (DT the) (NN stomach))))) (, ,) (NP (PRP it)) (VP (VP (VBZ begins) (S (VP (VBG mixing) (PP (IN with) (NP (JJ digestive) (NNS juices)))))) (CC and) (VP (VBZ is) (VP (VBN passed) (PP (IN into) (NP (DT the) (JJ small) (NN intestine))) (PP (NP (DT a) (JJ little)) (IN at) (NP (DT a) (NN time)))))) (. .)))
Once food enters the stomach, it begins mixing with digestive juices and is passed into the small intestine a little at a time.
(ROOT (S (NP (DT The) (JJ small) (NN intestine)) (VP (VBZ begins) (PP (IN in) (NP (DT the) (NN stomach)))) (. .)))