seeing a series of perfect black pearls clicking together to form a string 
(ROOT (S (VP (VBG seeing) (NP (NP (NP (DT a) (NN series)) (PP (IN of) (NP (JJ perfect) (JJ black) (NNS pearls)))) (VP (VBG clicking) (ADVP (RB together)) (S (VP (TO to) (VP (VB form) (NP (DT a) (NN string))))))))))
(ROOT (S (VP (VBG ) (NP (NP (NP (DT ) (NN )) (PP (IN ) (NP (JJ ) (JJ ) (NNS )))) (VP (VBG ) (ADVP (RB )) (S (VP (TO ) (VP (VB ) (NP (DT ) (NN ))))))))))