you wo n't be talking about the film once you exit the theater 
(ROOT (S (NP (PRP you)) (VP (MD wo) (RB n't) (VP (VB be) (VP (VBG talking) (PP (IN about) (NP (DT the) (NN film))) (SBAR (IN once) (S (NP (PRP you)) (VP (VBP exit) (NP (DT the) (NN theater))))))))))
(ROOT (S (NP (PRP )) (VP (MD ) (RB ) (VP (VB ) (VP (VBG ) (PP (IN ) (NP (DT ) (NN ))) (SBAR (IN ) (S (NP (PRP )) (VP (VBP ) (NP (DT ) (NN ))))))))))