( ( • Classify ) ( ( ( a sample ) of ) ( ( matter ( as ( ( a ( pure ( ( substance or ) mixture ) ) ) ( ( based ( on ( ( the number ) ( of ( ( elements or ) compounds ) ) ) ) ) ( in ( the sample ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (NNP •) (NNP Classify)) (ADVP (NP (DT a) (NN sample)) (IN of)) (VP (VBP matter) (PP (IN as) (NP (NP (DT a) (JJ pure) (NX (NX (NN substance)) (CC or) (NX (NN mixture)))) (VP (VBN based) (PP (IN on) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NNS elements) (CC or) (NNS compounds))))) (PP (IN in) (NP (DT the) (NN sample))))))) (. .)))
•  Classify a sample of matter as a pure substance or mixture based on the number of elements or compounds in the sample.
(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))))))) (. .)))