假设某城市人人所得税的税基为2000元，而其征收个人所得税的规定如下：不超过税基免征税，按超过税基部分征收所得税。超过部分在2000元以下，征税5 ；5000元以下，征税10 ；10000元以下，征税15 ；10000元以上，征税20 。-Suppose a city for all income tax base is 2000 yuan, and its personal income tax as follows: no more than tax-free tax base, tax base by more than part of the income tax. Excess of 2,000 yuan, tax of 5　 5,000 yuan, tax 10　 10,000 yuan, tax of 15　 more than 10,000 yuan, tax 20 .