( ( Samples ( of matter ) ) ( ( exist ( either ( ( ( as ( pure substances ) ) or ) ( as ( mixtures ( of ( pure substances ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Samples)) (PP (IN of) (NP (NN matter)))) (VP (VBP exist) (PP (CC either) (PP (IN as) (NP (JJ pure) (NNS substances))) (CC or) (PP (IN as) (NP (NP (NNS mixtures)) (PP (IN of) (NP (JJ pure) (NNS substances))))))) (. .)))
Samples of matter exist either as pure substances or as mixtures of pure substances.
(ROOT (S (NP (NNS Elements)) (VP (VBP are) (NP (NP (JJ pure) (NNS substances)) (SBAR (WHNP (WDT that)) (S (VP (VBP make) (ADVP (RB up) (DT all) (NN matter))))))) (. .)))