大全－III－8

8.     State X’s income-averaging law allows a portion of one’s income to be taxed at lower rate than the rate based on one’s total taxable income. To use income averaging, the taxpayer must have earned taxable income for a particular year that exceeds 140 percent of his or her average taxable income for the previous three years. People using income averaging owe less tax for that year than they would without income averaging.

Which of the following individuals would be most seriously affected if income averaging were not permitted in computing the taxes owed for current year?

(A) Individuals whose income has steadily decreased for the past three years

(B) Individuals whose income increased by 50 percent four years ago and has remained the same since then

(C) Individuals whose income has doubled this year after remaining about the same for five years

(D) Individuals who had no income this year, but did in each of the previous three years（C）

(E) Individuals who are retired and whose income has remained about the same for the past ten years

不明白红色部分的意思，请那为NN指点迷津

People using income averaging owe less tax for that year than they would without income averaging.

适用收入平均法的人那年将少交税（相比没有该法而言）。

補充一下~

We dont know how much the individual in A will make after their 3 years..so it's hard to tell whether they will be the most seriously affected ones..

个人认为，前面连续三年下降，但没有提到下降的幅度，所以第四年也未必能够达到题中要求－达到前三年平均值的140%；而C中明确指明Individuals whose income has doubled this year after remaining about the same for five years

The question asks: 如果不实行这种法律，哪部分人受的影响最大.

换个说法，新税法谁最占便宜？

It's obvious that those are the individuals whose income has doubled this year after remaining about the same for five years.

Plug in a number and do the calculation yourself,  and you will find out why.