( ( ( natural gas ) ( delivered ( through ( the pipelines ) ) ) ) ( also ( ( contains ( ( ( ( hydrocarbons ( such ( as ( ( ethane and ) propane ) ) ) ) , ) and ) ( ( other gases ) ( such ( as ( ( ( ( ( ( ( ( nitrogen , ) helium ) , ) ( carbon dioxide ) ) , ) ( hydrogen sulfide ) ) and ) ( water vapor ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (NP (JJ natural) (NN gas)) (VP (VBN delivered) (PP (IN through) (NP (DT the) (NNS pipelines))))) (ADVP (RB also)) (VP (VBZ contains) (NP (NP (NP (NNS hydrocarbons)) (PP (JJ such) (IN as) (NP (NN ethane) (CC and) (NN propane)))) (, ,) (CC and) (NP (NP (JJ other) (NNS gases)) (PP (JJ such) (IN as) (NP (NP (NN nitrogen)) (, ,) (NP (NNP helium)) (, ,) (NP (NN carbon) (NN dioxide)) (, ,) (NP (NN hydrogen) (NN sulfide)) (CC and) (NP (NN water) (NN vapor))))))) (. .)))
natural gas delivered through the pipelines also contains hydrocarbons such as ethane and propane, and other gases such as nitrogen, helium, carbon dioxide, hydrogen sulfide and water vapor.
(ROOT (S (NP (NP (DT The) (NN combustion)) (PP (IN of) (NP (NN propane) (NN gas)))) (VP (VBZ produces) (NP (NP (NN carbon) (NN dioxide)) (CC and) (NP (NN water) (NN vapor)))) (. .)))