( ( ( ( Methane , ) ( the ( simplest hydrocarbon ) ) ) , ) ( ( is ( ( a ( single ( carbon atom ) ) ) ( surrounded ( by ( four ( hydrogen atoms ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Methane)) (, ,) (NP (DT the) (JJS simplest) (NN hydrocarbon)) (, ,)) (VP (VBZ is) (NP (NP (DT a) (JJ single) (NN carbon) (NN atom)) (VP (VBN surrounded) (PP (IN by) (NP (CD four) (NN hydrogen) (NNS atoms)))))) (. .)))
Methane, the simplest hydrocarbon, is a single carbon atom surrounded by four hydrogen atoms.
(ROOT (S (NP (NNS Hydrocarbons)) (VP (VBP are) (VP (VBN made) (PP (IN of) (NP (NP (CD one) (NN carbon)) (CC and) (NP (CD four) (NN hydrogen) (NNS atoms)))))) (. .)))
Hydrocarbons are made of one carbon and four hydrogen atoms.