PREP 逻辑一题求解

oatmilk

When people evade income taxes by not declaring taxable income, a vicious cycle results. Tax evasion forces lawmakers to
raise income tax rates, which causes the tax burden on nonevading taxpayers to become heavier. This, in turn, encourages
even more taxpayers to evade income taxes by hiding taxable income. !
The vicious cycle described above could not result unless which of the following were true? !
(A) An increase in tax rates tends to function as an incentive for taxpayers to try to increase their pretax incomes.
(B) Some methods for detecting tax evaders, and thus recovering some tax revenue lost through evasion, bring in more than
they cost, but their success rate varies from year to year.
(C) When lawmakers establish income tax rates in order to generate a certain level of revenue, they do not allow adequately for
revenue that will be lost through evasion.
(D) No one who routinely hides some taxable income can be induced by a lowering of tax rates to stop hiding such income
unless fines for evaders are raised at the same time.
(E) Taxpayers do not differ from each other with respect to the rate of taxation that will cause them to evade taxes.

看了正确答案，想不明白。
先不说正确答案，大家一起讨论下吧，谢谢

DeliciaAn

When people evade income taxes by not declaring taxable income, a vicious cycle results. Tax evasion forces lawmakers to
raise income tax rates, which causes the tax burden on nonevading taxpayers to become heavier. This, in turn, encourages
even more taxpayers to evade income taxes by hiding taxable income.
The vicious cycle described above could not result unless which of the following were true?

当人们通过不报可税收入的方式逃税时，一个恶性循环就开始了。逃税强迫政策制定者提高税率，这又导致了没有逃税的纳税人的负担加重。这一结果反过来就会导致更多的人通过隐藏其可纳税收入来逃税。

（其实，后半句就是对那个a vicious cycle 进行了解释。）
问：下列除非哪个选项为真，要不这个vicious cycle 就不会发生。其实就是assumption吧。

(A) An increase in tax rates tends to function as an incentive for taxpayers to try to increase their pretax incomes.
增加的税率会刺激纳税人增加他们的税前收入。pretax income与vicious cycle涉及内容taxable income无关。删掉。 无故牵扯结合以外样本。
(B) Some methods for detecting tax evaders, and thus recovering some tax revenue lost through evasion, bring in more than
they cost, but their success rate varies from year to year.
一些方法被用来检测逃税者，通过逃税弥补税的收益的损失，带来比逃税者成本更高的收益，但是他们的成功率每年都在变化。（虽然我也不知道这个选项到底在讲啥，但是每年的逃税成功率跟题干问题也没啥关系，尤其是这里有but把后半句强调了出来，所以这个选项不选）
(C) When lawmakers establish income tax rates in order to generate a certain level of revenue, they do not allow adequately for
revenue that will be lost through evasion.
当政策制定者建立了收入税率为的是产生某个比率的收益，他们不允许通过逃税带来的收益消失。  这个就是原文中“逃税强迫政策制定者提高税率“这一逻辑链的加强。因为原文说：逃税－>lawmaker 提高税率。这个选项说明lawmaker为啥收到这些逃税人影响提高税率，就是为了generate a certain level of revenue.
(D) No one who routinely hides some taxable income can be induced by a lowering of tax rates to stop hiding such income
unless fines for evaders are raised at the same time.
没有人会隐藏自己的可税收入（这些可税收入是由于较低的税率）去停止隐藏自己的这一可税收入，除非对于这帮逃税的人的罚款也会同时提升。跟本没有提到罚款的事情。现在的罚款状况是怎样的，力度够不够，有没有效果等...所以这是无关选项。
(E) Taxpayers do not differ from each other with respect to the rate of taxation that will cause them to evade taxes.
对于将会导致人们逃税的税率来说，纳税人的行为基本没啥改变。这对原文没啥影响。即便有，也是削弱。因为，原文明确已经将纳税人分为了evading taxpayer和nonevading taxpayer.

oatmilk

DeliciaAn 发表于 2015-6-28 17:32
When people evade income taxes by not declaring taxable income, a vicious cycle results. Tax evasion ...

讲的非常清楚，明白了！非常感谢！