下列表达式中，弗里德曼的货币需求函数是（）。
A.MV=PT
B.
C.L=L1(+L2)
D.
参考答案：D
Julie enjoys listening music very much. She often says to me that _________ is more interesting than music. [ ]
A. nothing
B. something
C. everything
省煤器再循环的工作原理及作用如何？
