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问题 单项选择题 A1型题

样本含量分别为n1和n2的两样本率分别为P1和P2，则其合并平均率PC为（）

A.P1+P2

B.（P1+P2）／2

C.p1xP2

D.（n1P1+n2P2）／（n1+n1）

E.（n1-1）P1+（n2-1）P2／（n1+n2-2）

答案

参考答案：D

补全对话，情景问答

联系上下文，补全对话。

Danny is going to teach Li Ming to skate.

"         1          " says Danny.

"I think I can stand up." says Li Ming.

"Yes! Look, Danny!       2      "

"Good!" says  Danny. Danny stands up, too.

"       3        " asks Danny.

"I think I can." says Li Ming.

"Come on, Danny! "

"Oops!" says Danny. He falls down again.

"         4         " asks Danny.

"I think I can." says Li Ming. Li Ming skates backwards slowly.

"         5         " says Danny.

A. Very good, Li Ming!

B. Can you skate forwards?

C. I'm standing.

D. Can you stand up on the ice?

E. Can you skate backwards?
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单项选择题

申请凭证式国债承销团成员资格的申请人，其注册资本应不低于人民币（）亿元。

A．1

B．3

C．5

D．7
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