在其他情况不变的情况下，对于一般商品来说，随着收入的增加，需求会有所
A．上升
B．不变
C．不确定
D．下降
E．先上升后不变
参考答案：A
遭遇火灾时，我们应及时拨打电话（）
A、110
B、119
C、120
D、122
Which of the following conditions is most likely to exist for a typical production process when average product is at its maximum（）
A. Marginal product is increasing.
B. Marginal product is at a minimum.
C. Average variable cost is at a minimum.
