用双硫腙比色法测锌，锌离子与双硫腙生成的络合物的颜色是（）
A.橙色
B.黄色
C.紫红色
D.红色
E.绿色
参考答案：C
An analyst does research about the time value of money. An investor deposits $500 million in an account that eams a stated annual rate of 3.5% for the first year and 3.0% for the second year, compounded continuously. If there are no additional deposits or withdraws, the value of the account after two years is closest to:（）
A. $519.05 million.
B. $533.58 million.
C. $536.25 million.
1959年底至1960年初，毛 * * 在读苏联《政治经济学教科书》时，认为社会主义社会的发展阶段有
A．不发达的社会主义 B．比较发达的社会主义C．发达的社会主义 D．社会主义初级阶段
