NO.PZ2016010802000109
问题如下:
Following a sharp increase in the price of energy, the overall price level is most likely to rise in the short run:
选项:
A.and remain elevated indefinitely unless the central bank tightens.
B.but be unchanged in the long run unless the money supply is increased.
C.and continue to rise until all prices have increased by the same proportion.
解释:
B is correct.
An increase in energy prices will shift the short-run aggregate supply curve (SRAS) to the left, reducing output and increasing prices.
If there is no change in the aggregate demand curve, in particular if the central bank does not expand the money supply, slack in the economy will put downward pressure on in input prices, shifting the SRAS back to its original position. In the long run, the price level will be unchanged.
考点:AS曲线
解析:能源价格的攀升会造成总供给的衰退,总供给的衰退在长期会引起原材料价格的下降,从而使得总供给回到初始水平。这期间,如果该国央行不实施干预,那么总需求就不会发生改变。
总供给和总需求在长期都未改变的结果就是物价水平保持不变。
这个解析还是不懂,为什么AD要保持不变呢?能源价格的上升肯定是要影响AD呀,为什么AD不变呢?还是不太懂为什么能源价格上升就会使总供给下降,按道理价格的上升应该是move along啊,怎么出现shift呢?