( ( Ga ( means ( `` ( ( ( billions ( of ( years ago ) ) ) '' ) ( -RRB- ( You ( should ( know ( ( the ( ( names and ) order ) ) ( of ( ( the ( three eras ) ) ( of ( ( the Phanerozoic ) ( -LRB- ( ( ( ( ( Cenozoic , ) Mesozoic ) , ) Paleozoic ) -RRB- ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ( You ( ( should ( recognize ( ( period names ) ( -LRB- ( ( ( ( ( e.g. , ) Cambrian ) , ) ( Devonian ( , Cretaceous ) ) ) -RRB- ) ) ) ) ) . ) ) )
(ROOT (S (S (NP (NNP Ga)) (VP (VBZ means) (SBAR (S (`` ``) (NP (NP (NNS billions)) (PP (IN of) (NP (NP (NNS years)) (ADVP (IN ago)))) ('' '')) (-RRB- -RRB-) (VP (ADVP (PRP You)) (MD should) (VP (VB know) (NP (NP (DT the) (NNS names) (CC and) (NN order)) (PP (IN of) (NP (NP (DT the) (CD three) (NNS eras)) (PP (IN of) (NP (NP (DT the) (NNP Phanerozoic)) (PRN (-LRB- -LRB-) (NP (NNP Cenozoic)) (, ,) (NP (NNP Mesozoic)) (, ,) (NP (NNP Paleozoic)) (-RRB- -RRB-))))))))))))) (NP (PRP You)) (VP (MD should) (VP (VB recognize) (NP (NP (NN period) (NNS names)) (PRN (-LRB- -LRB-) (NP (NNP e.g.)) (, ,) (NP (NNP Cambrian)) (, ,) (NP (NNP Devonian) (, ,) (NNP Cretaceous)) (-RRB- -RRB-))))) (. .)))
Ga means &quot;billions of years ago&quot;) You should know the names and order of the three eras of the Phanerozoic (Cenozoic, Mesozoic, Paleozoic) You should recognize period names (e.g., Cambrian, Devonian, Cretaceous).
(ROOT (S (NP (NP (DT The) (JJ first) (NN period)) (PP (IN of) (NP (DT the) (JJ paleozoic) (NN era)))) (VP (VBD was) (VP (VBN called) (NP (NN cambrian)))) (. .)))