marshall keeps the energy humming , 
(ROOT (S (NP (NNP marshall)) (VP (VBZ keeps) (NP (DT the) (NN energy)) (S (VP (VBG humming)))) (, ,)))
(ROOT (S (NP (NNP )) (VP (VBZ ) (NP (DT ) (NN )) (S (VP (VBG )))) (, )))