( Limestone ( ( is ( indistinguishable ( from ( coal ( on ( most ( electric logs ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Limestone)) (VP (VBZ is) (ADJP (JJ indistinguishable) (PP (IN from) (NP (NP (NN coal)) (PP (IN on) (NP (JJS most) (JJ electric) (NNS logs))))))) (. .)))
Limestone is indistinguishable from coal on most electric logs.
(ROOT (S (NP (NNP Coal)) (VP (VBZ is) (NP (NP (DT the) (NN source)) (PP (IN of) (NP (JJS most) (NN electricity))))) (. .)))