PREP CR1上的题目，请教大家。。。

Sophin

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.

答案是C，请教各位的是怎么读这个题目，其实我倒着推理觉得C确实是最合适的，但是我单看题目的话就老是看不懂。。。
拜托各位了。。。

kartzzz

frankzheng43

感谢分享！               

xpyin

试着解释下：

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.

前提1：饮料瓶是1978年到1988年之间家庭垃圾总重量稳定下降的主要原因。
前提2：铝和玻璃回收的广泛使用是这个下降的原因。
前提3：铝回收比玻璃更普遍
前提4：玻璃重量下降的占家庭垃圾下降比例比铝还大
矛盾就是：为什么铝回收比玻璃更普遍，玻璃重量下降的占家庭垃圾下降比例比铝还大
其实这里有一个范畴GAP，就是前提1中提到的饮料瓶。

再看选项：
(A) Glass bottles are significantly heavier than aluminum cans of comparable size.玻璃瓶比铝瓶重。
这个不能解释，因为玻璃瓶和铝瓶的数量还是个变量
(B) Recycled aluminum cans were almost all beverage containers, but a significant fraction of the recycled glass bottles had contained products other than beverages.回收的铝瓶几乎都是饮料瓶，但是相当比例回收的玻璃瓶装的不是饮料。
说反了，照这个说法，铝应该占的比例更大
(C) Manufacturers replaced many glass bottles, but few aluminum cans, with plastic containers.
生产商用塑料瓶替换了一些玻璃瓶但是很少替换铝瓶。
说明铝瓶在源头上就少了，虽然回收比例大，但是在饮料瓶的数量少了，所以总比例还是少了。
(D) The total weight of glass bottles purchased by households increased at a slightly faster rate than the total weight of aluminum cans.
家庭购买的玻璃瓶重量增加速度比铝瓶重量略快。无关
(E) In many areas, glass bottles had to be sorted by color of the glass before being recycled, whereas aluminum cans required no sorting.在一些地方，玻璃瓶在回收之前按颜色分类，但是铝瓶不需要这样分类。
最无关了。

cynthia628

注意比较对象，结论it was found that the weight of glass bottles in household garbage declined by a greater percentage than the weight of aluminum cans.是glass bottles在recycle前后的重量减少量比铝罐在recycle前后的重量减少量更多。是一个绝对比较和相对比较的问题。而C说明，玻璃瓶之前是玻璃，后面换成了塑料，重量当然会减少的更多啦。

buffonjuventus

既然楼主对题目理解有问题，那么我就试着帮楼主解释一下题干吧：
From 1978 to 1988, beverage containers accounted for a steadily decreasing percentage of the total weight of household garbage in the United States.简要的白话翻译：从78~88，美国家庭垃圾重量稳定减少是由饮料瓶造成的。The increasingly widespread practice of recycling aluminum and glass was responsible for most of this decline.而其中大部分的下降又是由当时大量使用的可回收铝瓶和玻璃瓶造成的。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.可是即便（可回收）铝瓶的使用比（可回收）玻璃瓶的使用更加普遍，却还是发现（垃圾中）玻璃瓶重量下滑百分比要比铝瓶大。
问题可以理解为：以下哪个事实可以就这个finding做解释。
其实也就是可以理解为一下哪个事实可以解释题干中明显的paradox。题干中的paradox就是为什么铝瓶用的多却反而下降的没有玻璃瓶下降的多。
只能按照字面理解了。这个题目很搞，主要分母不明确。楼主别太较真，大概明白思路就可以了。