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题库 / Prep2007E1-CR-23
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?
Glass bottles are significantly heavier than aluminum cans of comparable size.
Recycled aluminum cans were almost all beverage containers, but a significant fraction of the recycled glass bottles had contained products other than beverages.
Manufacturers replaced many glass bottles, but few aluminum cans, with plastic containers.
The total weight of glass bottles purchased by households increased at a slightly faster rate than the total weight of aluminum cans.
In many areas, glass bottles had to be sorted by color of the glass before being recycled, whereas aluminum cans required no sorting.
②glass bottle在household garbage（家庭垃圾）中下降的比例更大==》注意：这里的比重就是指自身下降的重量与原来的重量比较，（现在的-原来的）/原来的，所以虽然玻璃瓶重，但是比影响比例大小
所以只可能是有其他的因素（非recycling practice）导致了玻璃瓶的大幅减少
gap：想一想，recycling是在末端减少玻璃瓶，有没有可能在生产端减少了玻璃瓶
c选项，因为玻璃被塑料替代的更多，所以不管是回收还是垃圾的比重都会下降得更多，所以c选项正确。
此题只考虑回收的量铝更多，但如果玻璃瓶使用得就少的话，一样可以解释题目中描述的现象。即C选项。A选项虽然glass bottle比铝盒重，但在不知glass bottle和铝盒的总的回收量的情形下无法解释现象。D选项犯和A选项一样的错误。E选项是无关选项。B选项是无关选项。
A其实很容易说明，原题上说的percentage， 也就是说是玻璃瓶减少的重量除以玻璃瓶重量比上铝罐减少重量除以铝罐重量，这就代表他们俩之间的重量关系是无所谓的。
但A不一定
c：生产玻璃瓶的少了，使用的总重也就少了
B. 1st sentence, topic of the discussion is limited to beverage packing in household garbage. The relative important of G and A in beverage can still be the same even more G is used for other products.
D: if the total G waste increase, but was recycled less than A, the rest G in garbage would only be even more.
AL recycling practice more wider → Glass bottles weight declined by a greater percentage
c, 生产商用塑料瓶替代了许多玻璃瓶 → 可以被recycle的就少了，自然减少的也多。
①aluminum回收实践的范围要比glass更广（暗示：应该aluminum在家庭垃圾中的占比下降更快）
②glass bottle在household garbage（家庭垃圾）中下降的比例更大==》注意：这里的比重就是指自身下降的重量与原来的重量比较，（现在的-原来的）/原来的，所以虽然玻璃瓶重，但是比影响比例大小
所以只可能是有其他的因素（非recycling practice）导致了玻璃瓶的大幅减少
gap：想一想，recycling是在末端减少玻璃瓶，有没有可能在生产端减少了玻璃瓶
C 它因问题
因为铝比玻璃瓶回收的范围广，所以垃圾里玻璃瓶重量下降的百分比比铝下降的快。所以要找支持玻璃瓶在垃圾里减少的选项。
A 原文说的是重量下降的百分比 和基数无关
B 和玻璃瓶中含有什么无关
C 玻璃瓶被塑料代替了，所以回收和垃圾里都会少。（他因，指出玻璃瓶减少的另一个原因）
D 购买的玻璃瓶总重量增长比比铝要快（百分比多不等于基数大）
E 无关