would n't have taken the protagonists a full hour to determine that in order to kill a zombie you must shoot it in the head 
(ROOT (S (VP (MD would) (RB n't) (VP (VB have) (VP (VBN taken) (NP (DT the) (NNS protagonists)) (NP (DT a) (JJ full) (NN hour)) (S (VP (TO to) (VP (VB determine) (SBAR (IN that) (S (SBAR (IN in) (NN order) (S (VP (TO to) (VP (VB kill) (NP (DT a) (NN zombie)))))) (NP (PRP you)) (VP (MD must) (VP (VB shoot) (NP (PRP it)) (PP (IN in) (NP (DT the) (NN head)))))))))))))))
(ROOT (S (VP (MD ) (RB ) (VP (VB ) (VP (VBN ) (NP (DT ) (NNS )) (NP (DT ) (JJ ) (NN )) (S (VP (TO ) (VP (VB ) (SBAR (IN ) (S (SBAR (IN ) (NN ) (S (VP (TO ) (VP (VB ) (NP (DT ) (NN )))))) (NP (PRP )) (VP (MD ) (VP (VB ) (NP (PRP )) (PP (IN ) (NP (DT ) (NN )))))))))))))))