( Oceans ( ( may ( contain ( ( ( localized currents ) , ) ( like ( ( ( the ( Gulf stream ) ) , ) ( that ( are ( ( mighty rivers ) ( flowing ( across ( a ( nearly ( stationary ocean ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Oceans)) (VP (MD may) (VP (VB contain) (NP (NP (VBN localized) (NNS currents)) (, ,) (PP (IN like) (NP (NP (DT the) (NNP Gulf) (NN stream)) (, ,) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (NP (NP (JJ mighty) (NNS rivers)) (VP (VBG flowing) (PP (IN across) (NP (DT a) (RB nearly) (JJ stationary) (NN ocean))))))))))))) (. .)))
Oceans may contain localized currents, like the Gulf stream, that are mighty rivers flowing across a nearly stationary ocean.
(ROOT (S (NP (DT A) (NN current)) (VP (VBZ is) (NP (NP (DT a) (NN stream)) (PP (IN of) (S (VP (VBG moving) (NP (NP (NN water)) (SBAR (WHNP (WDT that)) (S (VP (VBZ flows) (PP (IN through) (NP (DT the) (NN ocean)))))))))))) (. .)))