In phillips(1958) showed a strong and relatively stable negative relationship between unemployment and wage inflation. and then subsquent researchers found similar relationship between unemployment and price inflation, which then become well-known phillips curve, which appeared to be both theretical and empirical support for a stable unemployment-inflation tradeoff. But this point was shattered by Friedman's Natural-rate hypothesis in1960s. And one source of empirical faliure of philips curve is that supply shocks cannot explain all the falilings of he phillips curve in the 1970s and 1980s.