offers rare insight into the structure of relationships . 
(ROOT (S (VP (VBZ offers) (NP (NP (JJ rare) (NN insight)) (PP (IN into) (NP (NP (DT the) (NN structure)) (PP (IN of) (NP (NNS relationships))))))) (. .)))
(ROOT (S (VP (VBZ ) (NP (NP (JJ ) (NN )) (PP (IN ) (NP (NP (DT ) (NN )) (PP (IN ) (NP (NNS ))))))) (. )))