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问题 填空题

若a，b∈R，则a2+b2＜1是|a|+|b|＜1成立的______条件．

答案

∵a2+b2＜1时，（a，b）在以原点为圆心以1的半径的圆内，

此时|a|+|b|＜1不一定成立，

故a2+b2＜1是|a|+|b|＜1的不充分条件；

但当|a|+|b|＜1时，a2+b2＜1一定成立

故a2+b2＜1是|a|+|b|＜1的必要条件；

故a2+b2＜1是|a|+|b|＜1成立的必要而不充分条件

故答案为：必要而不充分

阅读理解

任务型阅读。

      I'm 13 years old. My birthday is April 21st. My sister is 15. Her birthday is July 2nd. I like basketball and baseball. But my sister does not like them. She likes volleyball. Every year we have a lot of events in

school. We have Art Festival in March. We have the school trip in May. We have English parties in

December ... How happy weare!

根据短文内容，回答下列问题。

1. When is the girl's birthday?

    ____________________________

2. When is her sister's birthday?

     ____________________________

3. When do they have their Art Festival?

    ____________________________

4. What sport does the girl like?

    ____________________________

5. When do they have their English parties?

    ____________________________
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填空题

分母是10的最小假分数是______．分子是7的真分数有______．
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