( ( ( PHYSICAL STATES ) ( OF ( ( MATTER Gas ) ( A gas ) ) ) ) ( ( is ( ( a substance ) ( which ( ( ( takes ( ( the shape ) ( of ( its container ) ) ) ) and ) ( expands ( to ( completely ( fill ( ( it 's ) container ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ PHYSICAL) (NNS STATES)) (PP (IN OF) (NP (NP (NNP MATTER) (NNP Gas)) (NP (DT A) (NN gas))))) (VP (VBZ is) (NP (NP (DT a) (NN substance)) (SBAR (WHNP (WDT which)) (S (VP (VP (VBZ takes) (NP (NP (DT the) (NN shape)) (PP (IN of) (NP (PRP$ its) (NN container))))) (CC and) (VP (VBZ expands) (S (VP (TO to) (VP (ADVP (RB completely)) (VB fill) (NP (NP (PRP it) (POS 's)) (NN container))))))))))) (. .)))
PHYSICAL STATES OF MATTER Gas A gas is a substance which takes the shape of its container and expands to completely fill it's container.
(ROOT (S (NP (DT A) (NN gas)) (VP (VBZ assumes) (NP (NP (DT the) (NN shape)) (PP (IN of) (NP (PRP$ its) (NN container))))) (. .)))