眼屈光系统成分中屈光力最大的为（）。
A.玻璃体
B.角膜
C.晶状体
D.房水
E.视网膜
参考答案：B
解析：眼屈光系统成分中屈光力最大的为角膜。
An analyst does research about correlation. The correlation of return between two securities with equal standard deviation is 0.75. If the covariance of returns in 5.5, the standard deviation of return of one security is closest to:（）
A. 2.7%
B. 5.7%
C. 7.3%
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