尿负荷实验可用于哪种营养素营养状况的评价（）
A.胡萝卜素
B.核黄素
C.1，25-（OH）2-D3
D.α-生育酚
E.以上都不是
参考答案：B
治疗腰脊强痛的穴位是（）
A.兑端
B.素髎
C.水沟
D.承浆
E.印堂
Assume thirty percent of the CFA candidates have a degree in economics. A random sample of three CFA candidates is selected. What is the probability that none of them has a degree in economics（）
A. 0.343.
B. 0.900.
C. 0.027.
