在二级的财务分析官方教材104页有讲到opening obligation can be viewed as the present value of benefits earned in prior years, 给出的公式是benefits earned in prior years/[(1+discount rate)^years until retirement]。但是benefits earned in prior years的现值不是应该用benefits earned in prior years乘以折现率来得到么，看得我很晕。请大家指点，谢谢。
