再问prep1-19，还是想不明白

19.       (27995-!-item-!-188;#058&003473)

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. (E)

ans E，取非后结论成立，那不就不可以选了吗？

取非以后，

增加食肉量的人急剧减少食谷量--->不用进口谷类了

跟原文相悖

不对啊，取非后

who increase their consumption of meat will radically decrease their consumption of grain--〉那就需要进口——〉和原文结论一致。。。