( ( North ( America ( , ( ( Australia and ) Antarctica ) ) ) ) ( ( ( are currently ) ( ( ( the ( only continents ) ) free ) ( of ( the disease ) ) ) ) . ) )
(ROOT (S (NP (NNP North) (NNP America) (, ,) (NNP Australia) (CC and) (NNP Antarctica)) (VP (VBP are) (ADVP (RB currently)) (NP (NP (DT the) (JJ only) (NN continents)) (ADVP (JJ free)) (PP (IN of) (NP (DT the) (NN disease))))) (. .)))
North America, Australia and Antarctica are currently the only continents free of the disease.
(ROOT (S (NP (NNP Antarctica)) (VP (VBZ is) (NP (NP (DT the) (JJ only) (NN continent)) (PP (IN without) (NP (NNS amphibians))))) (. .)))