不懂,请求帮助

In the years following an eight-cent increase in the federal tax on a pack of cigarettes, sales of cigarettes fell ten percent. In contrast, in the year prior to the tax increase, sales had fallen one percent. The volume of cigarette sales is therefore strongly related to the after-tax price of a pack of cigarettes.

The argument above requires which of the following assumptions?

1. During the year following the tax increase, the pretax price of a pack of cigarettes did not increase by as much as it had during the year prior to the tax increase.

2. The one percent fall in cigarette sales in the year prior to tax increases was due to a smaller tax increase.

3. The pretax price of a pack of cigarettes gradually decreased throughout the year before and the year after the tax increase.

4. For the year following the tax increase, the pretax price of a pack of cigarettes was not eight or more cents lower than it had been the previous year.

5. As the after-tax price of a pack of cigarettes rises, the pretax price also rises.

 做了好多次,可是又做错了,看来是根本上没理解.请NN指点

 做了好多次,可是又做错了,看来是根本上没理解.请NN指点

主要是搞清楚裸价/税/售价的关系

pretax/tax/aftertax

pretax 裸价+tax 税=after tax 售价

文章说sale和售价的关系密切，售价涨8分，sale跌10%

但是前提是pretax这个裸价在涨税那些年，不会跌，如果跌的幅度大于tax的幅度，那么就会使得售价会出现不变甚至小于原来的售价，这样的话，结论就不成立。D is correct

我发现了　

一定先把文章关系离出来