they will have a showdown , but , 
(ROOT (S (S (NP (PRP they)) (VP (MD will) (VP (VB have) (NP (DT a) (NN showdown))))) (, ,) (CC but) (, ,)))
(ROOT (S (S (NP (PRP )) (VP (MD ) (VP (VB ) (NP (DT ) (NN ))))) (, ) (CC ) (, )))