the gags are often a stitch . 
(ROOT (S (NP (DT the) (NNS gags)) (VP (VBP are) (ADVP (RB often)) (NP (DT a) (NN stitch))) (. .)))
(ROOT (S (NP (DT ) (NNS )) (VP (VBP ) (ADVP (RB )) (NP (DT ) (NN ))) (. )))