( ( ( ( pure substances ) ( -LRB- ( knowledge -RRB- ) ) ) ( Web Elements ) ) - )
(ROOT (NP (NP (NP (JJ pure) (NNS substances)) (PRN (-LRB- -LRB-) (NP (NN knowledge)) (-RRB- -RRB-)) (NP (NNP Web) (NNP Elements))) (: -)))
pure substances (knowledge) Web Elements -
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (DT a) (JJ pure) (NN substance)) (SBAR (WHNP (WDT that)) (S (VP (MD can) (RB not) (VP (VB be) (VP (VBN broken) (ADVP (RB down) (PP (IN into) (NP (NP (JJ different) (NNS types)) (PP (IN of) (NP (NNS substances)))))) (NP (DT a) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN element))))))))) (. .)))