( ( Since ( ( the ( killer robots ) ) ( may ( have ( been ( first ( built ( by ( ( ( ( humans , ) ( ( ( millions ( if not ) ) billions ) ( of ( years ago ) ) ) ) , ) ( then ( ( ( understanding and ) finding ) ( the solution ) ) ) ) ) ) ) ) ) ) ) ) ( , ( she ( ( ( ( ( argued , ) ( lay ( not ( ( ( ( in ( the future ) ) , ) but ) ( in ( the past ) ) ) ) ) ) , ) ( in ( the ( forgotten ( long ago ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Since) (S (NP (DT the) (NN killer) (NNS robots)) (VP (MD may) (VP (VB have) (VP (VBN been) (VP (ADVP (RB first)) (VBN built) (PP (IN by) (S (NP (NP (NNS humans)) (, ,) (NP (NP (NNS millions) (CONJP (IN if) (RB not)) (NNS billions)) (PP (IN of) (NP (NP (NNS years)) (ADVP (IN ago))))) (, ,)) (VP (ADVP (RB then)) (VBG understanding) (CC and) (VBG finding) (NP (DT the) (NN solution))))))))))) (, ,) (NP (PRP she)) (VP (VP (VBD argued)) (, ,) (VP (VBD lay) (PP (RB not) (PP (IN in) (NP (DT the) (NN future))) (, ,) (CC but) (PP (IN in) (NP (DT the) (NN past))))) (, ,) (PP (IN in) (NP (NP (DT the)) (VP (VBN forgotten) (ADVP (RB long) (RB ago)))))) (. .)))
Since the killer robots may have been first built by humans, millions if not billions of years ago, then understanding and finding the solution, she argued, lay not in the future, but in the past, in the forgotten long 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))))) (. .)))