( ( At ( mid-Cenozoic time ) ) ( , ( ( South America ) ( ( had ( ( ( ( ( a ( great variety ) ) ( of marsupials ) ) , ) but ) ( ( ( ( few ( placental mammals ) ) , ) and ) ( no ( large predators ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (JJ mid-Cenozoic) (NN time))) (, ,) (NP (NNP South) (NNP America)) (VP (VBD had) (NP (NP (NP (DT a) (JJ great) (NN variety)) (PP (IN of) (NP (NNS marsupials)))) (, ,) (CC but) (NP (NP (JJ few) (JJ placental) (NNS mammals)) (, ,) (CC and) (NP (DT no) (JJ large) (NNS predators))))) (. .)))
At mid-Cenozoic time, South America had a great variety of marsupials, but few placental mammals, and no large predators.
(ROOT (S (NP (JJ Placental) (NNS mammals)) (VP (VBP give) (NP (NN birth)) (PP (TO to) (NP (ADJP (RB relatively) (JJ large)) (NNS fetuses)))) (. .)))