问题如下：
4.Using the information in Exhibit 3 and Larsted's two assumptions, the effective tax rate should be closest to:
选项： 21% in 2012 and 27% in 2013.
21% in 2012 and subsequent years.
C.26% in 2012 and 27% in subsequent years.
解释：
4.A
“The result would be a 25% reduction in the amount of taxes charged in the current period and an increase by the same amount in the following period. ”我理解的是当年的税费降低25%，即1480*28%*（1-25%），以后每期都增加相同的数量，拿下一年来说就是1480*（1+10%）*28%+（1480*28%*25%），为什么答案中需要将税费降低25%后再加第一年减少的量？
