( ( Volume ( refers ( to ( ( the amount ) ( of space ) ) ) ) ) ( ( an object ) ( ( takes up ) . ) ) )
(ROOT (S (S (NP (NN Volume)) (VP (VBZ refers) (PP (TO to) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NN space))))))) (NP (DT an) (NN object)) (VP (VBZ takes) (PRT (RP up))) (. .)))
Volume refers to the amount of space an object takes up.
(ROOT (S (NP (NN Volume)) (VP (VBZ is) (NP (NP (DT a) (NN measure)) (PP (IN of) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NN space)))))) (SBAR (IN that) (S (NP (NP (DT a) (NN substance)) (CC or) (NP (DT an) (NN object))) (VP (VBZ occupies))))) (. .)))