官网Learning Module 4 Passive Equity Investing的EXAMPLE 2 Stratified Sampling，答案是先根据标普500指数里的成分股按市值排名来确定被动投资组合的成分数量；比如已选200个市值最大的成分股；然后在根据指数的行业板块权重来对所选的200个成分股同样分行业板块权重进行匹配调整，确保组合的这种分层抽样的成本和业绩更接近指数。我的问题是，既然是分层抽样，不是将指数先分行业板块，再在行业板块内按市值进行行业板块的权重调整？也避免不同行业板块可能市值规模不同，若先按市值筛选出成分股不一定能完全涵盖指数的行业板块？

图二问号那句话什么意思呀？为何到期日Gap就归0?

题干哪里说CHF贬值啊？limited upside指的是涨得不多吧，没有贬值的意思。答案怎么那么奇怪呢

rolldown return 是指折溢价债券回归面值的过程产生的，二级里的骑乘策略产生的收益是属于这个吗？

讲义都写了是期权的隐含波动，为什么还说是标的资产的？

老师，theta是time decay吗？时间流逝的越多，time decay越大，theta越小？

优点的第二点为什么passive factor based策略成本低于主动投资？另外缺点的最后一点passive cap weighted investing是什么投资策略？基础课PPT只有一次出现这个，这点不明白

第4题，请问答案这句话怎么理解呢The GIPS® composite should depict the results of an ongoing and consistent management process. While all the funds in the composite were briefly “non-discretionary” during this market disruption, this was an industry-wide event. The performance and dispersion impact on this fund was singularly significant and stemmed from a unique confluence of external circumstances not representative of the management style. It is large enough to compromise the integrity of the composite and be materially misleading to clients and prospects.

第2题，请问Reason 3为什么是对的，这个字眼看起来就很可疑“will eliminate the difficulties”。 Allowing the DFI funds to purchase shares in the POOL fund will eliminate the difficulties the investment team has had in achieving proper allocations and diversification in the DFI funds.

CFA三级-大类资产配置 relies on quantitative signals to capture documented return anomalies，focuses on value and momentum factors that have been determined to have explanatory power，我感觉既可以是均值回归，也可以是抓趋势，两种分析方式都可以用到，怎么区分呢？请教