老师，请问书本220页第十一题答案In order to take duration- neutral positions that will profit from an increase in the curvature of the yield curve, Hirji should structure a condor. Allocation to 2- year bond = Money duration of long- term bonds/PVBP of 2- year bond. duraion-neuture不是long+long=short+short，Money duration 2year+long-term=Money duratiion 5-year+ 10-year，为什么这里是Money duration 2-year=Money duration long-term？

老师，请问书本219页第九题答案 Options are added in anticipation of a significant change in rates是什么意思？为什么会change？怎么change？ foregone interest income on the liquidated bonds怎么理解？

老师，请问书本219页第七题答案A和C也能获利，为什么bullet是highset?三者如何计算和判断？

老师 请问这道题为什么选2呢 组合2的money duration并没有超过liability的money duration，如果是说差不多也可以的话，那什么范围内算是closely match呢

老师，请问书本217页第一题答案 Riding the yield curve differs from buy and hold in that the manager is expecting to add to returns by selling the security at a lower yield at the horizon. This strategy may be particularly effective if the portfolio manager targets portions of the yield curve that are relatively steep and where price appreciation resulting from the bond’s migration to maturity can be significant.是什么意思？ hold and buy和riding the curve如何区分？有没有时间的限定？hold 可以是任何年限，riding也是任何年限吗？那一年期限的是不是两个就没有区别？能否详细讲解一下两者的概念和异同点？有些分不清楚？

老师，请问书本300页第十五题答案As correlations increase, the values of the mezza-nine tranches usually increase relative to the values of the senior and equity tranches，课件视频中说subordinated ranches比senior好，那是不是mezzanin比subordinated好？

老师，请问书本300页第十一题答案 Once the credit universe has been divided into sectors, the investor identifies the bonds with the best relative value within each sector是什么意思？不太理解？

老师，请问书本300页第十题答案A benefit of the G- spread is that when the maturity of the credit security differs from that of the benchmark bond, the yields of two government bonds can be weighted so that their weighted average maturity matches the credit security’s maturity.是什么意思？如何reduces the potential for maturity mismatch？不太理解？

老师，请问书本298页第六题答案Spread sensitivity is the effect on credit spreads of large withdraw-als by investors from credit funds. Spread sensitivity can be measured as the spread widening (in basis points) divided by the percentage outflow from high- yield funds (funds withdrawn divided by assets under management). A decrease in the spread sensitivity to fund outflows would most likely indicate an increase in liquidity.是什么意思？不太理解？

老师，请问书本297页第二题答案，empirical duration is often estimated by running a regres-sion of its price returns on changes in a benchmark interest rate是什么意思？