From 1978 to 1988, beverage containers accounted for a steadily decreasing percentage of the total weight of household garbage in the United States. The increasingly widespread practice of recycling aluminum and glass was responsible for most of this decline. However, although aluminum recycling was more widely practiced in this period than glass recycling, it was found that the weight of glass bottles in household garbage declined by a greater percentage than the weight of aluminum cans.
Which of the following, if true of the United States in the period 1978 to 1988, most helps to account for the finding?
(A) Glass bottles are significantly heavier than aluminum cans of comparable size. (B) Recycled aluminum cans were almost all beverage containers, but a significant fraction of the recycled glass bottles had contained products other than beverages. (C) Manufacturers replaced many glass bottles, but few aluminum cans, with plastic containers. (D) The total weight of glass bottles purchased by households increased at a slightly faster rate than the total weight of aluminum cans. (E) In many areas, glass bottles had to be sorted by color of the glass before being recycled, whereas aluminum cans required no sorting.作者: colasama 时间: 2011-6-12 11:46
原文结论说declined by a greater percentage 注意percentage，跟glass和aluminum的本身重量就没关系了作者: lonelyorchid 时间: 2011-6-13 14:08
GMAT里所有关于比例改变的都有一个定式，新进入的和新退出的。
ERCENTAGE... 一定是比例上减少。 A 是一个迷惑选项