珠江三角洲地区与北京之间的铁路联系是（ ） A．京沪线和京广线 B．京九线和京广

—              are you from?    —I'm from China.[ ]

A. What        

B. How         

C. Where

等比数列{a_n}中，a₁+a₂=1，a₄+a₅=8，则公比q=______．

进行胃肠内营养，管饲时出现腹泻的可能原因有（）。

A.输注速度过快

B.抗生素使用过度致茵群失调

C.血清白蛋白低于30g／L

D.营养液被污染

E.营养液的渗透压过高

治疗风热或肝热目赤

A．麻黄配桂枝
B．麻黄配杏仁
C．麻黄配石膏
D．桂枝配白芍
E．桑叶、菊花

A portfolio manager is looking at an investment that has an expected annual return of 10% with a standard deviation of annual returns of 5%. Assuming the returns are approximately normally distributed, the probability that the return will exceed 20% in any given year is closest to:（）

A. 0.0%.

B. 4.56%.

C. 2.28%.