OG 123 提问

123. 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 of 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.

我觉得题目应该属于support 类型的, 对吗?就是说答案将会支持结论, 发生vicious cycle  这个结果.  对吗?

 答案是C ,但是想不明白, 特别是这句子的意思,: 制定税率是为了国家的税收,

他们充分地考虑到会被偷漏掉地税收部分  .  这个解释对么?

从逻辑上如何考虑这个题?

could not result unless XX were true = could result if XX were true