( ( When ( ( mercury compounds ) ( are ( used ( as ( catalysts ( for reactions ) ) ) ) ) ) ) ( , ( ( one alternative ) ( ( is ( to ( ( ( ( eliminate ( the catalyst ) ) and ) simply ) ( ( let ( the ( reaction run ) ) ) longer ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NN mercury) (NNS compounds)) (VP (VBP are) (VP (VBN used) (PP (IN as) (NP (NP (NNS catalysts)) (PP (IN for) (NP (NNS reactions))))))))) (, ,) (NP (CD one) (NN alternative)) (VP (VBZ is) (S (VP (TO to) (VP (VP (VB eliminate) (NP (DT the) (NN catalyst))) (CC and) (ADVP (RB simply)) (VP (VB let) (NP (DT the) (NN reaction) (NN run)) (ADVP (RBR longer))))))) (. .)))
When mercury compounds are used as catalysts for reactions, one alternative is to eliminate the catalyst and simply let the reaction run longer.
(ROOT (S (SBAR (IN If) (S (NP (DT a) (NN catalyst)) (VP (VBZ runs) (PRT (RP out))))) (, ,) (NP (DT the) (NN reaction)) (VP (VBZ slows)) (. .)))