arnold is not , nor will he be , back 
(ROOT (S (NP (NNP arnold)) (VP (VP (VBZ is) (RB not)) (, ,) (CC nor) (VP (MD will) (NP (PRP he)) (VP (VB be))) (, ,) (ADVP (RB back)))))
(ROOT (S (NP (NNP )) (VP (VP (VBZ ) (RB )) (, ) (CC ) (VP (MD ) (NP (PRP )) (VP (VB ))) (, ) (ADVP (RB )))))