这道题以前问过，但是还是没能解释我所不明白的地方，所以再问一次，原题如下：
122. 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 years 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.
我不明白的地方是问题，我记得not A unless B 的推理是A可以推出B吧？放到这里就是the vicious cycle described could result 能推出C答案这个说法,这好像说不通吧？我错在哪儿呢？作者: periodic 时间: 2005-7-10 16:28
提干的意思实际上是问以下那个选项为assumption？
显然答案是C
欢迎光临 国际顶尖MBA申请交流平台--TOPWAY MBA (http://forum.topway.org/)
