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问题 单项选择题 A1型题

在抗体形成过程中，下列哪些叙述是错误的（）

A.所有B细胞都必须有双信号刺激

B.Th细胞分泌细胞因子辅助B细胞活化

C.B细胞分化为浆细胞

D.浆细胞是抗体产生细胞

E.TI-Ag直接活化B细胞产生IgM

答案

参考答案：A

单项选择题

Which of the following statements about the role of the marginal cost of capital in determining the net present value of a project is most accurate The marginal cost of capital should be used to discount the cash flows:（）

A. if the firm’s capital structure is expected to change during the project’s life.

B. of all projects the firm is considering.

C. for potential projects that have a level of risk near that of the firm’s average project.
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