you 'd be wise to send your regrets 
(ROOT (S (NP (NP (PRP you))) (VP (MD 'd) (VP (VB be) (ADJP (JJ wise)) (S (VP (TO to) (VP (VB send) (NP (PRP$ your) (NNS regrets)))))))))
(ROOT (S (NP (NP (PRP ))) (VP (MD ) (VP (VB ) (ADJP (JJ )) (S (VP (TO ) (VP (VB ) (NP (PRP$ ) (NNS )))))))))