a rumor of angels does n't just slip -- 
(ROOT (S (NP (NP (DT a) (NN rumor)) (PP (IN of) (NP (NNS angels)))) (VP (VBZ does) (RB n't) (ADVP (RB just)) (VP (VB slip))) (: --)))
(ROOT (S (NP (NP (DT ) (NN )) (PP (IN ) (NP (NNS )))) (VP (VBZ ) (RB ) (ADVP (RB )) (VP (VB ))) (: )))