想问一下第三题，还是不太懂

Q. If an investor uses derivatives to make a long investment in commodities, the return earned on margin is best described as: A. convenience yield. B. collateral yield. C. price return. B is correct. Collateral yield is the return on cash used as margin on derivatives used to gain commodity exposure. A is incorrect because the convenience yield (also known as “roll yield”) is the return from rolling forward the maturity of the derivatives position. C is incorrect because price return is the difference between the forward and spot price. 请问老师，这个题目怎么理解？

啥意思？？？！？

老师，你好，请问下图如何理解？

为什么很多视频讲解声音这么小声，音量开到最大耳朵贴在喇叭上都听不到

听的糊里糊涂的

这节课听的很糊涂，最后的例子中，有两个每100 par value的价格一个是98.125，另一个是99.650。最后计算时为什么用99.650而不是98.125？

老师，你好，为何计算rd时，都是%数？

另外，如上题，先求出的是发债融资的YTM，即为融资收益率——意为：融资收益率X（1-t）=税后债务成本，这样理解可有问题?

左图中将费用分成了ordinary expense，other expense和loss，那在右图的列式中是不是COGS对应ordinary expense？SG&A和利息费用、税费等都属于other expense吗，还是other expense应该出现在operating profit计算EBIT的过程中？