金锁固精丸的主治症状不包括
A.遗精滑泄B.神疲乏力C.四肢酸软D.小便频数.
参考答案:D
枇杷叶的主要化学成分是
A.蒽醌类B.生物碱类C.皂苷类D.香豆素类E.黄酮类
An analyst does research about correlation. In a portfolio of two risky securities, the portfolio risk is maximized when the two securities are.()
A. uncorrelated.
B. perfectly positively correlated.
C. perfectly negatively correlated.