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问题 选择题

下列结论正确的是（　　）

A．幂函数的图象一定过原点

B．当α＜0时，幂函数y=xα是减函数

C．当α＞0时，幂函数y=xα是增函数

D．函数y=x2既是二次函数，也是幂函数

答案

①中，当α=0时，00无意义，幂函数y=xα不可能过原点，不正确；

②中，α＜0时，幂函数y=xα在（0，+∞）上为减函数，但不一定幂函数y=xα在整个定义域上是减函数，错误．

③中，α=2时，幂函数y=xα在（-∞，0）上为减函数，错误；

④中，函数y=x2既是二次函数，也是幂函数，正确．

故选D．

完形填空

第二节根据对话内容，从对话后的选项中选出能填入空白处的最佳选项.选项中有两项多余选项. （共5小题，每小题1分，满分5分）

W: How did you like the English Evening organized by the first-year students?

M: ___61__. I thought some of the items were wonderful.

W: ___62_.

M: Well, the group singing was good, and the storytelling was also interesting. And I especially liked the poem recited by the girl with long pigtails. ___63___.

W: How about the play on by Class Six? ___64___.Their intonation was a bit faulty here and there, but the acting was good. They certainly did an excellent job.

M: ___65__.And they wrote the play themselves, you know.

A: I thought it quite a success.

B: I don’t think so.

C: Very much indeed.

D: I agree with you.

E: She’s got such good pronunciation.

F: Which did you like best?

G: Very disappointing.
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单项选择题

财务内部收益率是指项目在整个计算期内各年净现金流量现值累计等于零时的折现率。它反映的是项目全部投资所能获得的（）。

A.最低收益率

B.最大利润率

C.最高收益率

D.平均利润率
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