( Scientists ( generally ( ( ( base ( scientific hypotheses ) ) ( on ( ( previous observations ) ( that ( ( ( can not ) satisfactorily ) ( be ( explained ( with ( the ( available ( scientific theories ) ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (NNS Scientists)) (ADVP (RB generally)) (VP (VBP base) (NP (JJ scientific) (NNS hypotheses)) (PP (IN on) (NP (NP (JJ previous) (NNS observations)) (SBAR (WHNP (WDT that)) (S (VP (MD can) (RB not) (ADVP (RB satisfactorily)) (VP (VB be) (VP (VBN explained) (PP (IN with) (NP (DT the) (JJ available) (JJ scientific) (NNS theories))))))))))) (. .)))
Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories.
(ROOT (S (NP (NNS Scientists)) (VP (VBP explain) (NP (DT the) (NN world)) (PP (VBN based) (PP (IN on) (NP (NNS observations))))) (. .)))