your first instinct is to duck 
(ROOT (S (NP (PRP$ your) (JJ first) (NN instinct)) (VP (VBZ is) (S (VP (TO to) (VP (VB duck)))))))
(ROOT (S (NP (PRP$ ) (JJ ) (NN )) (VP (VBZ ) (S (VP (TO ) (VP (VB )))))))