问题如下：
A client has asked you to explain the differences between potential GDP and real GDP:
选项：
A.Growth in potential GDP measures how rapidly the total economy is expanding.
B.If real GDP is below potential GDP, the aggregate price level has downward pressure.
C.If real GDP is below potential GDP, the aggregate price level tends to rise.
解释：
B is correct.
Growth in real GDP measures how rapidly the total economy is expanding. If real GDP is below potential GDP, the aggregate price level has downward pressure. If real GDP is above potential GDP, the aggregate price level has upward pressure.
考点：potential GDP
解析：是真实GDP而非potential GDP 能够准确衡量一国GDP的增长情况，所以A选项不入选。
如果当前真实GDP小于potential GDP ，表明该国当前经济不景气，物价就可能面临下行压力，所以B选项正确，而C选项错误。
老师，好：
这道题目选B可以理解。但是c项，如果是供给冲击，导致stagflation，real也＜potential，那么价格不是tends to rise么？
