( products ( ( is ( ( reduced ( by ( ( non-selective reactions ) ( of ( methyl radicals ) ) ) ) ) ( with ( ( the ( ( surface and ) oxygen ) ) ( in ( ( ( the ( gas phase ) ) , ) ( which ( ( produce ( -LRB- ( undesirable -RRB- ) ) ) ( carbon ( monoxide ( and ( carbon dioxide ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS products)) (VP (VBZ is) (VP (VBN reduced) (PP (IN by) (NP (NP (JJ non-selective) (NNS reactions)) (PP (IN of) (NP (NN methyl) (NNS radicals))))) (PP (IN with) (NP (NP (DT the) (NN surface) (CC and) (NN oxygen)) (PP (IN in) (NP (NP (DT the) (NN gas) (NN phase)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBP produce) (PRN (-LRB- -LRB-) (VB undesirable) (-RRB- -RRB-)) (NP (NN carbon) (NN monoxide) (CC and) (NN carbon) (NNS dioxide))))))))))) (. .)))
products is reduced by non-selective reactions of methyl radicals with the surface and oxygen in the gas phase, which produce (undesirable) carbon monoxide and carbon dioxide.
(ROOT (S (NP (NNP Combustion) (NNS reactions)) (VP (VBP involve) (S (NP (NP (DT the) (NN reaction)) (PP (IN of) (NP (NP (DT a) (NN hydrocarbon)) (PP (IN with) (NP (NN oxygen) (NN gas)))))) (VP (TO to) (VP (VB produce) (NP (NN water) (CC and) (NN carbon) (NN dioxide)))))) (. .)))