求解答~旧prep2-50

liuyinghong

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?

(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.

B哪里错？C又哪里对？？
天啊~越看B越有道理……
另外，这道题算是哪种体型呢？假设？
求大侠点拨

momohe

是一个隐含假设题。

Tax evasion forces lawmakers to raise income tax rates, which causes the tax

burden on nonevading taxpayers to become heavier.

有人逃税导致其他人的税负更高，隐含的假设是：有人逃税之后，政府仍然希望税收总量

不要减少，因此在不逃税的人身上收取更高的税作为弥补。这样才造成恶性循环。
假如政府任凭逃税的人导致税收总量减少，不因此提高税率增加不逃税者的负担，则不会

导致恶性循环。

c正是这个必须的假设，所以c是必须的。

B和这个逻辑无关。你为什么会越看越B对呢

Fuckitup

(B) is wrong because the presence of the word "some" twice.  Some = 1 or

100 in a scale of 1 to 100.  But if some =1, then answer B won't deter MOST

tax evaders from evading tax year in and year out.

The devil is in the detail.

liuyinghong

B为什么不对？？

zhangluE

我说下c为什么对吧，想了半天，觉得是这样的，原题的意思是法律的制定者通过提高所得税来保证税收，这样会导致更多的人逃税，是一个恶性循环。而这个恶性循环的条件就是提高所得税会让更多人逃税，c的意思就是当提高税率时能同时保证没有人逃税，因而就不会陷入恶性循环。。。