(S (BASENP (NNP Statoil)) (VP (VP (VBZ admits) (PRN (COMMA ,) (ADVP (RB however)) (COMMA ,))) (SBAR (IN that) (S (NP (BASENP (JJ heavy) (NN oil) (NN production)) (PRN (COMMA ,) (NP (BASENP (JJ such)) (SBAR (IN as) (S (VP (VBZ is) (VP (VBN required) (PP (IN in) (BASENP (DT the) (NN oil) (NNS sands)))))))) (COMMA ,))) (QTR (QTC (VP (VP (VBZ is) (QTL (DQL ``) (ADJP (ADJP (NN energy) (JJ intensive)) (CC and) (ADJP (JJ challenging))))) (PP (IN in) (BASENP (DT an) (JJ environmental) (NN perspective)))) (PERIOD .)) (DQR ''))))))