In the long run, when the economy is at full employment, will a decrease in the quantity of money due to restrictive monetary policy that brings a decrease in aggregate demand likely result in: the price level real GDP（）①A. No No ②B. No Yes ③C. Yes No

A. ①

B. ②

C. ③

用括号中的试剂或方法除去下列物质中所含杂质，错误的是（　　）

A．铜粉中混有铁粉（稀硫酸）

B．CaO中混有CaCO₃（高温煅烧）

C．KCl溶液中混有K₂CO₃（稀盐酸）

D．CO₂中混有CO（点燃）