63. Which of the following events will most likely result in a decrease in a valuation allowance for a deferred tax asset under U.S. GAAP (generally accepted accounting principles)? A(n):
A. reduction in tax rates.
B. decrease in interest rates.
C. increase in the carry forward periods available under the tax l

这道题我是用排除法做的，首先Valuation allowance我理解的是坏账准备，A和B选项都不会受其影响，所以我选的C，但是感觉根本原理没有理解，请大神指点。

64. A company presents its financial statements according to U.S. GAAP (generally accepted accounting principles) and has just issued $5 million of mandatory redeemable preferred shares with a par value of $100 per share and a 7% dividend. The issue matures in 5 years. Which of the following statements is least likely correct? At the time of the issue, the company’s:
A. debt-to-total capital ratio will improve
B. interest coverage ratio will deteriorate.
C. preferred shareholders will rank below debt holders should the company file for bankruptcy.

题目问的是哪一个是不正确的，我觉得A是正确的呀，Debt to capital ratio虽然分子分母都增加，但是分子增加的更多一些，所以我觉得A是增加的呀，但是答案是A，感觉问的好奇怪。

102. A bond has a modified duration of 6.5 and convexity of -42.4. If interest rates decrease by 1.0 percent, the percentage change in the value of the bond will be closest to:
A. -6.92%.
B. +2.76%.
C. +6.08%.

这道题目我记得就是公式，我的算法是(-Duration × Δy* × 100%) + (1/2 × (Δy*)2 × 100%)
= (-6.5 × -0.01 × 100%) + (1/2 ×(-42.4) × (-0.01)2 × 100%) = +6.5% - 0.21% = +6.29%.
这样就没答案了，答案是C。解释如下：The percentage change in the bond’s value is equal to:
(-Duration × Δy* × 100%) + (C × (Δy*)2 × 100%)
= (-6.5 × -0.01 × 100%) + (-42.4 × (-0.01)2 × 100%) = +6.5% - 0.424% = +6.08
唯一跟我不一样的是没有乘以1/2....我不明白为什么这里不用乘1/2

问题比较多，谢谢大家了。