engages us in constant fits of laughter 
(ROOT (S (VP (VBZ engages) (NP (PRP us)) (PP (IN in) (NP (NP (JJ constant) (NNS fits)) (PP (IN of) (NP (NN laughter))))))))
(ROOT (S (VP (VBZ ) (NP (PRP )) (PP (IN ) (NP (NP (JJ ) (NNS )) (PP (IN ) (NP (NN ))))))))