Group 1 - The article discusses the obligation to pay vehicle purchase tax when a vehicle that has previously been exempted or reduced from tax is transferred or its purpose is changed within ten years [4] - Taxpayers must pay the vehicle purchase tax before transferring or changing the registration of the vehicle if it no longer qualifies for exemption or reduction [4] - The tax obligation arises on the date of transfer or change of use, and the taxable amount is based on the initial tax declaration price, with a deduction of 10% for each year of use [4] Group 2 - The calculation formula for the tax payable is provided, indicating that the tax amount cannot be negative and the usage period is calculated from the date of the initial tax declaration to the date the vehicle no longer qualifies for exemption [4] - The article specifies the locations where taxpayers should declare and pay the vehicle purchase tax, including the tax authority at the vehicle registration location [5]