necessary viewing for sci-fi fans 
(ROOT (NP (NP (JJ necessary) (NN viewing)) (PP (IN for) (NP (NML (NN sci-) (NN fi)) (NNS fans)))))
(ROOT (NP (NP (JJ ) (NN )) (PP (IN ) (NP (NML (NN ) (NN )) (NNS )))))