( ( Nitrogen oxides ) ( ( ( are ( pollutants ( ( produced ( by ( ( the reaction ) ( of ( ( nitrogen and ) oxygen ) ) ) ) ) ( when ( ( high temperatures ) ( are ( generated ( in ( internal ( combustion ( ( engines and ) furnaces ) ) ) ) ) ) ) ) ) ) ) . ) -RRB- ) )
(ROOT (S (NP (NN Nitrogen) (NNS oxides)) (VP (VBP are) (NP (NP (NNS pollutants)) (VP (VBN produced) (PP (IN by) (NP (NP (DT the) (NN reaction)) (PP (IN of) (NP (NN nitrogen) (CC and) (NN oxygen))))) (SBAR (WHADVP (WRB when)) (S (NP (JJ high) (NNS temperatures)) (VP (VBP are) (VP (VBN generated) (PP (IN in) (NP (JJ internal) (NN combustion) (NNS engines) (CC and) (NNS furnaces)))))))))) (. .) (-RRB- -RRB-)))
Nitrogen oxides are pollutants produced by the reaction of nitrogen and oxygen when high temperatures are generated in internal combustion engines and furnaces.)
(ROOT (S (NP (NNP Nitrogen)) (VP (VBZ oxide) (NP (NP (NN form)) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-)) (SBAR (WHADVP (WRB when)) (S (NP (NN nitrogen) (CC and) (NN oxygen)) (VP (VBP combine) (PP (IN at) (NP (JJ high) (NNS temperatures)))))))) (. .)))