57题中，如果两个是非完全线性是什么样的啊，完全线性不需要增加相同的数量吧，是不是只需要保持一样的斜率？

选项b，只有利息的贷款是什么意思，麻烦老师解释下

什么情况下产生a？

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

老师 28题这个 为什么7.0037%都要加上一个OAS？ 是因为callable bond 里z spread= oas+ int ？ 那putable就是oas-int=z spread么？这么理解吗？

听的糊里糊涂的