sex with strangers is fascinating ... 
(ROOT (S (NP (NP (NN sex)) (PP (IN with) (NP (NNS strangers)))) (VP (VBZ is) (ADJP (JJ fascinating))) (. ...)))
(ROOT (S (NP (NP (NN )) (PP (IN ) (NP (NNS )))) (VP (VBZ ) (ADJP (JJ ))) (. )))