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问题 单项选择题

气泡吸收管使用前要进行吸收效率实验，要求1个管的采样效率达到（）

A.80%以上

B.75%以上

C.85%以上

D.70%以上

E.90%以上

答案

参考答案：E

阅读理解

根据短文内容回答问题。

Dear Amy,

     How are you ? My name is David. I'm an American boy.  For me,  sports are fun. I have a collection

 of sports things. I have six basketballs , three tennis rackets, nine volleyballs, four soccer balls, and five

  baseballs. I play sports and I watch them on TV. Do you play sports?Do you have a sports collection?

1.  Is David American?                         

    _____ , _____ 

2. Are sports fun for David?                  

    _____  ,  _____ 

3. Does David have a collection of sports things?   

    _____  ,  _____ 

4. How many baseballs does he have?            

    _______________________.

5. Where does David watch sports ?  

    _______________________.       
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单项选择题

各国财政收入最重要的收入形式和最主要的收入来源是( )。

A．国债收入

B．国有资产收益

C．收费收入

D．税收
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