( ( Only ( since ( the 1980s ) ) ) ( ( ( ( ( ( have reconstructions ) , ) ( based ( on ( ( significant amounts ) ( of data ) ) ) ) ) , ) ( shown ( ( ( ( the paths ) ( of ( the continents ) ) ) and ) ( ( the ages ) ( of ( the ( ocean basins ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (RB Only) (RB since) (DT the) (NNS 1980s)) (VP (VBP have) (NP (NNS reconstructions)) (, ,) (PP (VBN based) (PP (IN on) (NP (NP (JJ significant) (NNS amounts)) (PP (IN of) (NP (NNS data)))))) (, ,) (VP (VBN shown) (NP (NP (NP (DT the) (NNS paths)) (PP (IN of) (NP (DT the) (NN continents)))) (CC and) (NP (NP (DT the) (NNS ages)) (PP (IN of) (NP (DT the) (NN ocean) (NNS basins))))))) (. .)))
Only since the 1980s have reconstructions, based on significant amounts of data, shown the paths of the continents and the ages of the ocean basins.
(ROOT (S (S (NP (DT This) (NN process)) (ADVP (RB usually)) (VP (VBZ takes) (NP (NP (DT the) (JJS longest) (NN amount)) (PP (IN of) (NP (NN time)))))) (: :) (S (NP (DT an) (NN ocean) (NN basin)) (VP (VBZ forms) (PP (IN between) (NP (CD two) (NNS continents))))) (. .)))
This process usually takes the longest amount of time: an ocean basin forms between two continents.