伤寒患者出现玫瑰疹，多见于
A．潜伏期B．发病初期C．高热期D．缓解期E．恢复期
参考答案：C
An investor opens a margin account with an initial deposit of $5000. He then purchases 300 shares of a stock at $30. His margin account has a maintenance margin requirement of 30 percent. Ignoring commissions and interest, the price at which the investor receives a margin call is closest to.（）
A. $14.26.
B. $18.72.
C. $19.05.
分子量小的亲水性化学物通过生物膜的方式（）。
A.简单扩散
B.易化扩散
C.滤过
D.膜动运动
E.主动转运
