为什么这里只用到2017的数据，不用所有数据求平均呢？

问题如下：

Steve is considering investing PZ Inc. and he asks three of his analysts to forecast the 2018 income statement for PZ. Based on the following information and Phil’s key assumptions, Phil’s forecast for cost of sales in 2018 is closest to:

选项：

$34.5 million

$55.5 million

$70.1 million

解释：

B is correct.

考点：Income Statement Modeling: Revenue

解析：B是正确的。Phil预计，2018年的毛利率将比2017年增加40个基点，净销售额将比名义GDP增速快70个基点的。因此，预计2018年的销售成本为5,550万美元。