are frequently too dark to be decipherable 
(ROOT (VP (VBP are) (ADVP (RB frequently)) (ADJP (RB too) (JJ dark) (S (VP (TO to) (VP (VB be) (ADJP (JJ decipherable))))))))
(ROOT (VP (VBP ) (ADVP (RB )) (ADJP (RB ) (JJ ) (S (VP (TO ) (VP (VB ) (ADJP (JJ ))))))))