So effectively, the hometown tax system is the most direct and most frequently used part of tax deductibility that is actually available.
因此，实际上，家乡税收制度是实际可用的税收减免中最直接、最常用的部分。
英语百科
Tax deduction
（重定向自Deductibility）
Tax deduction is a reduction of income that is able to be taxed, and is commonly a result of expenses, particularly those incurred to produce additional income. The difference between deductions, exemptions and credit is that deductions and exemptions both reduce taxable income, while credits reduce tax.