The students often play games _________ Tuesday. [ ]
A. in
B. at
C. on
D. from
答案:C
《国语·晋语》载:“宗庙之牲为畎亩之勤”这反映了 ( )。
A.牛耕的出现
B.牛耕的推广
C.铁农具的使用
D.周王室的日益衰微
简述资源经营的特征?