GWD-2-18 大家听我一个讲垃圾回收站的故事：去年。。。。

Last year all refuse collected by Shelbyville city services was incinerated.  This incineration generated a large quantity of residue ash.  In order to reduce the amount of residue ash Shelbyville generates this year to half of last year’s total, the city has revamped its collection program.  This year city services will separate for recycling enough refuse to reduce the number of truckloads of refuse to be incinerated to half of last year’s number. 

Which of the following is required for the revamped collection program to achieve its aim?

A.       This year, no materials that city services could separate for recycling will be incinerated.

B.       Separating recyclable materials from materials to be incinerated will cost Shelbyville less than half what it cost last year to dispose of the residue ash.

C.       Refuse collected by city services will contain a larger proportion of recyclable materials this year than it did last year.

D.       The refuse incinerated this year will generate no more residue ash per truckload incinerated than did the refuse incinerated last year.

E.        The total quantity of refuse collected by Shelbyville city services this year will be no greater than that collected last year.

答案是D, 我认为选C. 原因如下，大家发表自己意见！！！

total amount of ash = # of trucks * ash per truck

Provided by question: "last year all refuse ... was incinerated", so no recycled.... Now, city decided to "speparate for recycle".

C = this year's recycle items's proportion will be higher (last year is zero), so it will decrease the "#of trucks" --> decrease total amount of ASH.

D = decrease "ash per truck" , but if #of trucks lower down a lot by recycle, even you have increased "ash per truck" --> total amount still can go down !!  So, WRONG.