问题如下：
The difference between the yield on a zero-coupon, default-free nominal bond and the yield on a zero-coupon, default-free real bond of the same maturity reflects:
选项：
A.investors’ expectations about future inflation only.
B.a premium for the uncertainty of future inflation only.
C.both, investors’ expectations about future inflation and a premium for the uncertainty of future inflation.
解释：
C is correct.
The difference between the yield on a zero-coupon, default-free nominal bond and the yield on a zero-coupon, default-free real bond of the same maturity is known as the break-even inflation rate. This break-even inflation rate will incorporate the inflation expectations of investors over the investment horizon of the two bonds, plus a risk premium to compensate investors for uncertainty about future inflation. Breakeven inflation rates are not simply the markets’ best estimate of future inflation over the relevant investment horizon, as break-even inflation rates also include a risk premium to compensate investors for their uncertainty about future inflation.
考点：break-even inflation rate
解析：对于长期无风险零息债券而言，其名义利率包括实际利率、预期通货膨胀以及对非预期的通货膨胀的补偿；而实际无风险债券的收益率就是实际利率。二者的差就是预期通货膨胀和对非预期的通货膨胀的补偿两部分，这两部分之和即break-even inflation rate.
如果是短期债券的话，就不应该考虑uncertain的部分了吧？
只有长期债券的，才考虑uncertain和expected
