( ( Live ( in ( ( the form ) ( of ( single-celled organisms ) ) ) ) ) ( ( ( ( appeared ( ( ( about ( 3 billion ) ) years ) ago ) ) , ) ( with ( ( ( more complex ) ( life forms ) ) ( evolving ( ( ( about ( 2 billion ) ) years ) later ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Live)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (JJ single-celled) (NNS organisms)))))) (VP (VBD appeared) (ADVP (NP (QP (RB about) (CD 3) (CD billion)) (NNS years)) (RB ago)) (, ,) (PP (IN with) (NP (NP (ADJP (RBR more) (JJ complex)) (NN life) (NNS forms)) (VP (VBG evolving) (ADVP (NP (QP (RB about) (CD 2) (CD billion)) (NNS years)) (RB later)))))) (. .)))
Live in the form of single-celled organisms appeared about 3 billion years ago, with more complex life forms evolving about 2 billion years later.
(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))))) (. .)))