a comedy to start a reaction 
(ROOT (NP (NP (DT a) (NN comedy)) (SBAR (S (VP (TO to) (VP (VB start) (NP (DT a) (NN reaction))))))))
(ROOT (NP (NP (DT ) (NN )) (SBAR (S (VP (TO ) (VP (VB ) (NP (DT ) (NN ))))))))