( ( The ( first marsupials ) ) ( ( may ( have ( evolved ( ( ( about ( 130 million ) ) years ) ago ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ first) (NNS marsupials)) (VP (MD may) (VP (VB have) (VP (VBN evolved) (ADVP (NP (QP (RB about) (CD 130) (CD million)) (NNS years)) (RB ago))))) (. .)))
The first marsupials may have evolved about 130 million years ago.
(ROOT (S (NP (DT The) (JJ first) (VBG living) (NNS cells)) (VP (MD may) (VP (VB have) (VP (VBN evolved) (ADVP (NP (QP (RB around) (CD 4) (CD billion)) (NNS years)) (RB ago))))) (. .)))