( ( ( ( Matter ( ( is either ) ( a mixture ) ) ) or ) ( it ( is ( a ( pure substance ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Matter)) (VP (VBZ is) (RB either) (NP (DT a) (NN mixture)))) (CC or) (S (NP (PRP it)) (VP (VBZ is) (NP (DT a) (JJ pure) (NN substance)))) (. .)))
Matter is either a mixture or it is a pure substance.
(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))))))) (. .)))