( ( A gas ) ( ( is ( ( ( a form ) ( of matter ) ) ( that ( ( does not ) ( have ( ( ( a ( defined shape ) ) or ) volume ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN gas)) (VP (VBZ is) (NP (NP (DT a) (NN form)) (PP (IN of) (NP (NN matter))) (SBAR (WHNP (WDT that)) (S (VP (VBZ does) (RB not) (VP (VB have) (NP (NP (DT a) (JJ defined) (NN shape)) (CC or) (NP (NN volume))))))))) (. .)))
A gas is a form of matter that does not have a defined shape or volume.
(ROOT (S (NP (NP (DT The) (NN gas) (NN form)) (PP (IN of) (NP (NN matter)))) (VP (VBZ has) (NP (NP (ADVP (DT neither)) (DT a) (JJ definite) (NN shape)) (CC nor) (NP (DT a) (JJ definite) (NN volume)))) (. .)))