(S (S (S (NP (NP (BASENP (DT The) (NN line)) (PP (IN on) (BASENP (DT a) (NN graph)))) (SBAR (WHNP (WDT that)) (S (VP (VBD plotted) (BASENP (NN oil) (NN price)))))) (VP (VBD had) (VP (VP (VBN done) (BASENP (DT a) (JJ steady) (NN incline))) (PP (IN over) (BASENP (JJ recent) (NNS years)))))) (COMMA ,) (SBAR (IN though) (S (S (BASENP (JJ many) (NNS factors)) (VP (VBP are) (VP (VBN involved) (PP (IN in) (NP (BASENP (DT the) (NN price)) (PP (IN of) (NP (BASENP (DT a) (NN barrel)) (PP (IN of) (BASENP (NN oil)))))))))) (SBAR (IN so) (S (BASENP (PRP it)) (VP (VP (VBZ is) (ADJP (RB almost) (JJ impossible))) (S (VP (TO to) (VP (VB say) (SBAR (WHADVP (WRB how) (RB much)) (S (NP (BASENP (DT the) (NNS troubles)) (PP (IN in) (BASENP (NNP Iraq)))) (VP (VBD contributed) (PP (TO to) (BASENP (DT this) (NN rise))))))))))))))) (PERIOD .))