( ( Some homes ) ( ( are ( ( built ( on ( ( mountains or ) float ) ) ) ( on ( the ocean ) ) ) ) . ) )
(ROOT (S (NP (DT Some) (NNS homes)) (VP (VBP are) (VP (VBN built) (PP (IN on) (NP (NNS mountains) (CC or) (NN float))) (PP (IN on) (NP (DT the) (NN ocean))))) (. .)))
Some homes are built on mountains or float on the ocean.
(ROOT (S (NP (NNS Scientists)) (VP (VBP know) (SBAR (IN that) (S (NP (DT some) (NNS mountains)) (VP (VBD were) (ADVP (RB once)) (PP (IN at) (NP (NP (DT the) (NN bottom)) (PP (IN of) (NP (DT an) (NN ocean))))) (SBAR (IN because) (S (NP (JJ marine) (NNS fossils)) (VP (VBP have) (VP (VBN been) (VP (VBN found) (PP (IN on) (NP (NP (DT the) (NNS peaks)) (PP (IN of) (NP (DT some) (NNS mountains)))))))))))))) (. .)))