( ( ( A gas ) ( in ( a ( closed container ) ) ) ) ( ( ( will completely ) ( take ( ( the shape ) ( of ( the container ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NN gas)) (PP (IN in) (NP (DT a) (VBN closed) (NN container)))) (VP (MD will) (ADVP (RB completely)) (VP (VB take) (NP (NP (DT the) (NN shape)) (PP (IN of) (NP (DT the) (NN container)))))) (. .)))
A gas in a closed container will completely take the shape of the 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))))) (. .)))