... an interesting slice of history . 
(ROOT (FRAG (, ...) (NP (NP (DT an) (JJ interesting) (NN slice)) (PP (IN of) (NP (NN history)))) (. .)))
(ROOT (FRAG (, ) (NP (NP (DT ) (JJ ) (NN )) (PP (IN ) (NP (NN )))) (. )))