一个市场需求的上限,也就是市场需求函数的最大值是指()。
参考答案:市场潜力
He works in a factory now, but he on a farm for 20 years.
A.worked
B.has worked
C.had worked
D.had been working
银行电子化系统有()特点。
A、及时有效
B、准确可靠
C、连续可扩
D、开放和功能丰富
E、安全保密