4000,7,1,30,5,9
—Sorry, Frank. I'm busy today. I can't go swimming with you.
—_________[ ]
A. No problem
B. You're welcome
C. That's all
D. Never mind
楚汉战争时,有“米石万钱”的记载,而据《太平御览》,汉文帝时,谷价至于石数十钱。后甚至有“每石粟至十余钱”的历史记录。导致粮价降低的主要原因是
A.农民劳动积极性的大幅提高
B.汉朝正确的农业政策
C.农耕经济的不断发展
D.战争期间粮价上涨,和平时期降低