( ( ( ( Elements and ) Compounds ) ( An element ) ) ( ( is ( ( a substance ) ( that ( ( can not ) ( be ( ( reduced ( to ( a ( simpler substance ) ) ) ) ( by ( chemical means ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNPS Elements) (CC and) (NNPS Compounds)) (NP (DT An) (NN element))) (VP (VBZ is) (NP (NP (DT a) (NN substance)) (SBAR (WHNP (WDT that)) (S (VP (MD can) (RB not) (VP (VB be) (VP (VBN reduced) (PP (TO to) (NP (DT a) (JJR simpler) (NN substance))) (PP (IN by) (NP (NN chemical) (NNS means)))))))))) (. .)))
Elements and Compounds An element is a substance that cannot be reduced to a simpler substance by chemical means.
(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))))))))) (. .)))