( ( Upon ( the tides ) ) ( ( As ( ( a bubble ) ( on ( the water ) ) ) ) ( I ( ( did float ) . ) ) ) )
(ROOT (S (PP (IN Upon) (NP (DT the) (NNS tides))) (PP (IN As) (NP (NP (DT a) (NN bubble)) (PP (IN on) (NP (DT the) (NN water))))) (NP (PRP I)) (VP (VBD did) (NP (NN float))) (. .)))
Upon the tides As a bubble on the water I did float.
(ROOT (S (NP (NNP Gas) (NN bubble) (NNS holes)) (VP (VBZ helps) (NP (NP (JJ pumice) (NN float)) (PP (IN in) (NP (NN water))))) (. .)))