( ( Their action ) ( ( ( could not ) ( be ( ( ( explained ( by ( ( Archimedes ' ) Law ) ) ) , ) ( since ( ( ( the amount ) ( of ( fluid ( they ( displace ( as ( they ( walk ( on water ) ) ) ) ) ) ) ) ) ( ( does not ) ( correspond ( to ( ( a force ) ( sufficient ( to ( ( keep them ) ( from sinking ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP$ Their) (NN action)) (VP (MD could) (RB not) (VP (VB be) (VP (VBN explained) (PP (IN by) (NP (NP (NNP Archimedes) (POS ')) (NN Law))) (, ,) (SBAR (IN since) (S (NP (NP (DT the) (NN amount)) (PP (IN of) (S (VP (VBG fluid) (S (NP (PRP they)) (VP (VB displace) (SBAR (IN as) (S (NP (PRP they)) (VP (VBP walk) (PP (IN on) (NP (NN water)))))))))))) (VP (VBZ does) (RB not) (VP (VB correspond) (PP (TO to) (NP (NP (DT a) (NN force)) (ADJP (JJ sufficient) (S (VP (TO to) (VP (VB keep) (NP (PRP them)) (PP (IN from) (NP (VBG sinking)))))))))))))))) (. .)))
Their action could not be explained by Archimedes' Law, since the amount of fluid they displace as they walk on water does not correspond to a force sufficient to keep them from sinking.
(ROOT (S (NP (NP (NNP Archimedes) (POS ')) (NN law)) (VP (VBZ explains) (SBAR (WHADVP (WRB why)) (S (NP (NP (DT a) (NN ship)) (VP (VBG weighing) (NP (NP (NNS thousands)) (PP (IN of) (NP (JJ metric) (NNS tons)))))) (VP (VBZ floats) (PP (IN on) (NP (NN water))))))) (. .)))