( ( ( The ( sudden ( mass extinction ) ) ) ( of dinosaurs ) ) ( ( ( is still ) ( a ( mystery today ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ sudden) (NN mass) (NN extinction)) (PP (IN of) (NP (NNS dinosaurs)))) (VP (VBZ is) (ADVP (RB still)) (NP (DT a) (NN mystery) (NN today))) (. .)))
The sudden mass extinction of dinosaurs is still a mystery today.
(ROOT (S (NP (NP (ADJP (JJ Sudden) (CC and) (JJ dramatic)) (NNS losses)) (PP (IN of) (NP (NN biodiversity)))) (VP (VBP are) (VP (VBN called) (NP (JJ mass) (NN extinction)))) (. .)))