答案错了吧

NO.PZ2018091701000019 问题如下 investor proposes buying a one-yegovernment zero-coupon bonwith favalue of $100 anprice$97.5, investor also collectesome market information, the one-yererisk-free rate 1.56% anunexpecteinflation is 2.12% last year, please calculate the implieexpecteinflation rate for the one-yegovernment zero-coupon bon A.1.1% B.-1.1% C.2.5% B is correct.考点计算公式P t= ( C F t+s )/( 1+ l t,1 + θ t,1+ π t,1 ) s解析根据题干提供的已知变量，倒推出未知变量θ97.5=100/(1+ 1.56%+θ+2.12%) 可以计算出θ=-0.011 or -1.1% 如题

NO.PZ2018091701000019 问题如下 investor proposes buying a one-yegovernment zero-coupon bonwith favalue of $100 anprice$97.5, investor also collectesome market information, the one-yererisk-free rate 1.56% anunexpecteinflation is 2.12% last year, please calculate the implieexpecteinflation rate for the one-yegovernment zero-coupon bon A.1.1% B.-1.1% C.2.5% B is correct.考点计算公式P t= ( C F t+s )/( 1+ l t,1 + θ t,1+ π t,1 ) s解析根据题干提供的已知变量，倒推出未知变量θ97.5=100/(1+ 1.56%+θ+2.12%) 可以计算出θ=-0.011 or -1.1% 老师，这里unexpecteinflation is 2.12% last year这个去年的预期外通胀率为什么要加上呢？这里计算的不是今年的预期通胀率么？跟去年的有什么关系呢？

NO.PZ2018091701000019问题如下investor proposes buying a one-yegovernment zero-coupon bonwith favalue of $100 anprice$97.5, investor also collectesome market information, the one-yererisk-free rate 1.56% anunexpecteinflation is 2.12% last year, please calculate the implieexpecteinflation rate for the one-yegovernment zero-coupon bonA.1.1%B.-1.1%C.2.5%B is correct.考点计算公式P t= ( C F t+s )/( 1+ l t,1 + θ t,1+ π t,1 ) s解析根据题干提供的已知变量，倒推出未知变量θ97.5=100/(1+ 1.56%+θ+2.12%) 可以计算出θ=-0.011 or -1.1%前面的学习不是说 zero coupon bon的r 与rerisk free rate的差就是expecteunexpecteinflation吗？那通过100/（1+r）=97.5反推出来 r是0.02564 则expecte0.02564-0.0156-0.0212=-0.0112，是这么理解吗？

老师你好，短期债券不是忽略“预期通胀不确定性”（PAI）的风险吗？