not only to record the events for posterity , but to help us 
(ROOT (S (CONJP (RB not) (RB only)) (VP (TO to) (VP (VB record) (NP (DT the) (NNS events)) (PP (IN for) (NP (NN posterity))))) (, ,) (CC but) (VP (TO to) (VP (VB help) (NP (PRP us))))))
(ROOT (S (CONJP (RB ) (RB )) (VP (TO ) (VP (VB ) (NP (DT ) (NNS )) (PP (IN ) (NP (NN ))))) (, ) (CC ) (VP (TO ) (VP (VB ) (NP (PRP ))))))