( ( This oxygen ) ( ( is ( ( ( ( ( the gas ) ( which ( supports ( ( combustion , ) ( ( in that ) ( it ( alone ( ( combines ( with ( hydrocarbons ( such ( as ( gasoline ( , ( alcohol ( , ( and ( diesel fuel ) ) ) ) ) ) ) ) ) ) ) ( to ( produce ( ( ( carbon dioxide ) and ) ( water vapor ) ) ) ) ) ) ) ) ) ) ) ) , ) and ) ( ( heat , ) ( which ( causes ( ( ( these ( two products ) ) ( of combustion ) ) ( ( ( to expand ) and ) ( to ( ( ( ( exert pressure ) ( on pistons ) ) , ) ( driving ( the engine ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN oxygen)) (VP (VBZ is) (NP (NP (NP (DT the) (NN gas)) (SBAR (WHNP (WDT which)) (S (VP (VBZ supports) (NP (NP (NN combustion)) (, ,) (SBAR (WHPP (IN in) (WHNP (WDT that))) (S (NP (PRP it)) (VP (ADVP (RB alone)) (VBZ combines) (PP (IN with) (NP (NP (NNS hydrocarbons)) (PP (JJ such) (IN as) (NP (NN gasoline) (, ,) (NN alcohol) (, ,) (CC and) (NN diesel) (NN fuel))))) (S (VP (TO to) (VP (VB produce) (NP (NP (NN carbon) (NN dioxide)) (CC and) (NP (NN water) (NN vapor)))))))))))))) (, ,) (CC and) (NP (NP (NN heat)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ causes) (S (NP (NP (DT these) (CD two) (NNS products)) (PP (IN of) (NP (NN combustion)))) (VP (VP (TO to) (VP (VB expand))) (CC and) (VP (TO to) (VP (VB exert) (NP (NN pressure)) (PP (IN on) (NP (NNS pistons))) (, ,) (S (VP (VBG driving) (NP (DT the) (NN engine)))))))))))))) (. .)))
This oxygen is the gas which supports combustion, in that it alone combines with hydrocarbons such as gasoline, alcohol, and diesel fuel to produce carbon dioxide and water vapor, and heat, which causes these two products of combustion to expand and to exert pressure on pistons, driving the engine.
(ROOT (S (NP (NNP Combustion) (NNS reactions)) (VP (VBP involve) (S (NP (NP (DT the) (NN reaction)) (PP (IN of) (NP (NP (DT a) (NN hydrocarbon)) (PP (IN with) (NP (NN oxygen) (NN gas)))))) (VP (TO to) (VP (VB produce) (NP (NN water) (CC and) (NN carbon) (NN dioxide)))))) (. .)))