grab us , only to keep letting go at all the wrong moments 
(ROOT (S (VP (VB grab) (NP (PRP us)) (, ,) (S (ADVP (RB only)) (VP (TO to) (VP (VB keep) (S (VP (VBG letting) (NP (VB go)) (PP (IN at) (NP (PDT all) (DT the) (JJ wrong) (NNS moments)))))))))))
(ROOT (S (VP (VB ) (NP (PRP )) (, ) (S (ADVP (RB )) (VP (TO ) (VP (VB ) (S (VP (VBG ) (NP (VB )) (PP (IN ) (NP (PDT ) (DT ) (JJ ) (NNS )))))))))))