NO.PZ2016012102000101
问题如下：
An analyst forecasting a company's earning would be least likely to
选项：
A.key financial ratio will be unchange.
B.use common-size financial statement to forecast expenses as a percentage of gross income.
C.use common-size financial statement to forecast expenses as a percentage of reveune.
解释：
B is correct.
Forcast earnings usually estimate expenses as a percentage of reveune but not gross income.
考点：公司利润预测
这题的意思是在问，公司做利润预测的时候，最不正确的做法是什么。
A选项：假设主要财务比率不变。正确。
B 选项：我们通常预测费用时候，认为费用和毛利(gross income)呈正比。错误。
C选项：我们通常预测费用时候，认为费用和销量呈正比关系，这个说法是对的。
请问解析中，怎么看出选项B是成正比？？？
