Gortland has long been narrowly self-sufficient in both grain and meat. However, as per capita income in Gortland has risen toward the world average, per capita consumption of meat has also risen toward the world average, and it takes several pounds of grain to produce one pound of meat.  Therefore, since per capita income continues to rise, whereas domestic grain production will not increase, Gortland will soon have to import either grain or meat or both.

Which of the following is an assumption on which the argument depends?

(A) The total acreage devoted to grain production in Gortland will soon decrease.

(B) Importing either grain or meat will not result in a significantly higher percentage of Gortlanders' incomes being spent on food than is currently the case.

(C) The per capita consumption of meat in Gortland is increasing at roughly the same rate across all income levels.

(D) The per capita income of meat producers in Gortland is rising faster than the per capita income of grain producers.

(E) People in Gortland who increase their consumption of meat will not radically decrease their consumption of grain.

   不明白为什么选E

谷物和肉的关系是 ，N多谷物产1斤肉

如果都去吃肉，不吃谷物，那么多出来的谷物可以产肉，以弥补肉的需求，这样又自给自足了。

可是结论不是Gortland will soon have to import either grain or meat

or both.吗？

意思就是不能自给自足阿？

是啊，所以E是not，即否定了我之前说的内容

即不会出现自己自足的情况，需要进口

我之前说的其实是对E的取非