( ( At sea ) ( , ( ( when ( ( the wind ) ( is ( blowing ( ( the surface ) ( of ( the ocean ) ) ) ) ) ) ) ( ( the waves ) ( ( are tossed ) . ) ) ) ) )
(ROOT (S (PP (IN At) (NP (NN sea))) (, ,) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN wind)) (VP (VBZ is) (VP (VBG blowing) (NP (NP (DT the) (NN surface)) (PP (IN of) (NP (DT the) (NN ocean)))))))) (NP (DT the) (NNS waves)) (VP (VBP are) (VP (VBN tossed))) (. .)))
At sea, when the wind is blowing the surface of the ocean the waves are tossed.
(ROOT (NP (NP (NNP Ocean) (NNS waves) (NN travel)) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-)) (PP (IN at) (NP (NP (DT the) (NN interface)) (PP (IN between) (NP (NP (DT the) (NN sea) (NN surface)) (CC and) (NP (DT the) (NN atmosphere)))))) (. .)))