uses a totally unnecessary prologue , just because it seems obligatory 
(ROOT (S (VP (VBZ uses) (NP (DT a) (ADJP (RB totally) (JJ unnecessary)) (NN prologue)) (, ,) (SBAR (ADVP (RB just)) (IN because) (S (NP (PRP it)) (VP (VBZ seems) (S (ADJP (JJ obligatory)))))))))
(ROOT (S (VP (VBZ ) (NP (DT ) (ADJP (RB ) (JJ )) (NN )) (, ) (SBAR (ADVP (RB )) (IN ) (S (NP (PRP )) (VP (VBZ ) (S (ADJP (JJ )))))))))