( ( ( The atmosphere ) ( on Titan ) ) ( ( ( ( contains ( ( a lot ) ( of ( the ( gas nitrogen ) ) ) ) ) , ) ( like ( what ( we ( ( have here ) ( on Earth ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN atmosphere)) (PP (IN on) (NP (NNP Titan)))) (VP (VBZ contains) (NP (NP (DT a) (NN lot)) (PP (IN of) (NP (DT the) (NN gas) (NN nitrogen)))) (, ,) (PP (IN like) (SBAR (WHNP (WP what)) (S (NP (PRP we)) (VP (VBP have) (NP (RB here)) (PP (IN on) (NP (NNP Earth)))))))) (. .)))
The atmosphere on Titan contains a lot of the gas nitrogen, like what we have here on Earth.
(ROOT (S (NP (NN Nitrogen) (NN gas)) (VP (VBZ comprises) (NP (NP (QP (RB about) (NNS three-fourths))) (PP (IN of) (NP (NP (NN earth) (POS 's)) (NN atmosphere))))) (. .)))