(S (S (S (S (BASENP (DT This)) (VP (VP (VBZ does) (RB not)) (VP (VB occur)))) (SBAR (WHADVP (WRB when)) (S (BASENP (NN fuel) (NN demand)) (VP (VBZ is) (ADJP (JJR lower)))))) (COMMA ,) (SBAR (IN as) (S (BASENP (DT the) (JJ hot) (NN oil)) (VP (ADVP (RB then)) (VP (VBZ becomes) (ADJP (JJ sufficient) (S (VP (TO to) (VP (ADVP (RB entirely)) (VP (VB melt) (BASENP (DT the) (NN ice)))))))))))) (PERIOD .))