a compelling yarn , but not quite a ripping one . 
(ROOT (NP (NP (DT a) (JJ compelling) (NN yarn)) (, ,) (CC but) (RB not) (PDT quite) (DT a) (VBG ripping) (NN one) (. .)))
(ROOT (NP (NP (DT ) (JJ ) (NN )) (, ) (CC ) (RB ) (PDT ) (DT ) (VBG ) (NN ) (. )))