自我清除菌斑的主要手段应是
A．漱口B．使用牙线C．刷牙D．洁治术E．使用牙签
参考答案：C
Analysis of two mutual funds, a stock fund-S and a bond fund B, yields the following results: S: Expected Return=0.14 Standard deviation=0.24 B: Expected Return=0.08 Standard deviation=0.14 Covariance between rates of return for S and B=0.00672 A portfolio with equal amounts of S and B will have expected return and standard deviation of:()
A. 0.11 and 0.0580.
B. 0.11 and 0.1393.
C. 0.19 and 0.1393.
在Visual FoxPro中说明数组的命令是 ______。
A．DIMENSION~ARRAY
B．DECLARE~ARRAY
C．DIMENSION和D欧九A1lE
D．只有DIMENSION
