( Catalysts ( ( are ( ( required ( for ( the reaction ) ) ) ( to ( be usable ) ) ) ) ; ) )
(ROOT (S (NP (NNS Catalysts)) (VP (VBP are) (VP (VBN required) (PP (IN for) (NP (DT the) (NN reaction))) (S (VP (TO to) (VP (VB be) (ADJP (JJ usable))))))) (: ;)))
Catalysts are required for the reaction to be usable;
(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)) (. .)))