( ( Gas ( bubbles ( and ( water samples ) ) ) ) ( ( were ( ( collected and ) analyzed ) ) . ) )
(ROOT (S (NP (NNP Gas) (NN bubbles) (CC and) (NN water) (NNS samples)) (VP (VBD were) (VP (VBN collected) (CC and) (VBN analyzed))) (. .)))
Gas bubbles and water samples were collected and analyzed.
(ROOT (S (NP (NNP Gas) (NN bubble) (NNS holes)) (VP (VBZ helps) (NP (NP (JJ pumice) (NN float)) (PP (IN in) (NP (NN water))))) (. .)))