问题如下：
2. The events of 2004 to 2006 would be expected to:
选项：
A.bias the historical equity risk premium estimate upwards.
B.bias the historical equity risk premium estimate downwards.
C.have no effect on the historical equity risk premium estimate.
解释：
B is correct.
The events of 2004 to 2006 depressed share returns but 1) are not a persistent feature of the stock market environment, 2) were not offset by other positive events within the historical record, and 3) have led to relatively low valuation levels, which are expected to rebound.
老师你看我的想法对不对，首先战争肯定影响股价下跌，投资者对股票的估值肯定也相应降低，如果Price小了，那么r就大了，r大了，ERP就会变大，为啥答案是ERP bias downward呢？如果从ERP的公式角度出发，确实Rm变的更低了，但是rf也可能减小了啊，而且ERP可能还有别的小尾巴之类的，比如流动性补偿之类的，怎么想都是ERP变大了啊，也和讲义的说法更贴合，ERP与经济周期负相关（下图标红处）。
