( Photosynthesis ( ( evolved ( ( ( around ( 3.4 billion ) ) years ) ago ) ) . ) )
(ROOT (S (NP (NNS Photosynthesis)) (VP (VBD evolved) (ADVP (NP (QP (RB around) (CD 3.4) (CD billion)) (NNS years)) (RB ago))) (. .)))
Photosynthesis evolved around 3.4 billion 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))))) (. .)))