( They ( ( know ( how ( ( ( ( the heart ) and ) lungs ) ( ( work together ) ( to ( keep ( oxygen ( supplied ( to ( the body ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBP know) (SBAR (WHADVP (WRB how)) (S (NP (NP (DT the) (NN heart)) (CC and) (NP (NNS lungs))) (VP (VBP work) (ADVP (RB together)) (S (VP (TO to) (VP (VB keep) (NP (NP (NN oxygen)) (VP (VBN supplied) (PP (TO to) (NP (DT the) (NN body)))))))))))) (. .)))
They know how the heart and lungs work together to keep oxygen supplied to the body.
(ROOT (S (PP (IN In) (NP (PRP$ your) (NN body))) (, ,) (NP (NP (DT the) (NN heart)) (CC and) (NP (NNS lungs))) (VP (VBP work) (ADVP (RB together)) (S (VP (TO to) (VP (VB make) (ADJP (JJ sure)) (SBAR (IN that) (S (NP (NN oxygen)) (VP (VBZ gets) (PP (TO to) (NP (NP (PDT all) (DT the) (JJ other) (NNS organs)) (PP (IN of) (NP (PRP$ your) (NN body)))))))))))) (. .)))
In your body, the heart and lungs work together to make sure that oxygen gets to all the other organs of your body.