交感神经阻滞不用于：（）
A.严重风湿性关节痛
B.灼样神经痛
C.带状疱疹
D.青诺综合征
E.偏头痛
参考答案：A
Nortel Industries has a preferred stock outstanding that pays (fixed) annual dividends of $3.75 a share. If an investor wants to earn a rate of return of 8.5 percent, how much should he be willing to pay for a share of Nortel preferred stock（）
A. $44.12.
B. $31.88.
C. $37.50.
活塞环卡住应采取更换活塞环。
