又是一道比例题,数学不差呀,乍就不会做

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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.

 我选的A,答案是C, 不明白,请NN指点

hehe,又碰到mm了，偶不是nn,来说两句看能不能帮到mm

铝的recycling比glass多，说明在正常使用量下，铝在生活垃圾中占的比例应该下降的比glass多；（循环使用的次数越多，所需要的总量就越少）但是finding却是glass的比例下降的较多：

原来的重量x循环次数=所需要的总重量

A:我们现在只知道循环次数方面AL>Glass,如果A,glass较重,但是这个重量是GLASS与生俱来的，对等式的另外两个变量不能起到任何作用；

C:更多的塑料瓶代替了玻璃瓶，说明对glass上面等式中“原来的重量”大为减少，虽然循环次较少，但还是有可能相乘得到的总重量少于Al

问题的关键可能是对RECYCLING的理解,通过答案LST怎么理解PROCESS OF RECYCLING?  THANKS A LOT