( It ( ( is ( ( a gas ) ( at ( room temperature ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (NP (NP (DT a) (NN gas)) (PP (IN at) (NP (NN room) (NN temperature))))) (. .)))
It is a gas at room temperature.
(ROOT (S (NP (NNP Hydrogen)) (VP (VBZ is) (PP (IN in) (NP (NP (NN gas) (NN form)) (PP (IN at) (NP (NN room) (NN temperature)))))) (. .)))