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问题 填空题

关系操作的特点是（）操作。

答案

参考答案：集合

解析：

在关系操作中，所有操作对象与操作结果都是关系。关系定义为元数相同的元组的集合。因此，关系操作的特点是集合操作。

判断题

判断题。（正确的打“√”，错误的打“×”）

1．小数的位数越多，这个小数就越大。[ ]

2．读小数时，整数部分和小数部分都按照整数的读法来读。  [ ]

3．0.6和0.60大小相同，计数单位不相同。[ ]

4．5.19在自然数5和6之间，它近似于5。  [ ]

5．0.496保留两位小数是0.5。 [ ]
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填空题

根据句意和首字母或汉意完成单词。

1. —What would you do if you had a million dollars? —I'd give it to c_________.

2. Pandas are Mary's f_________ animals.

3. He finds watching movies f_________ because the people speak too quickly.

4. I'm t_________ (害怕) of the dark, so I never go out in the evening.

5. There is a s_________ (奇怪的) smell in the room. Do you know what it is?

6. You have to be 18 years old before you are a_________ to drive a car.

7. Did you know potato chips were i_________ by mistake?

8. If you study hard, I'm sure you will s_________.

9. The librarian has put the library books on those s_________ neatly; you can find the book you want easily.

10. What would you do if you i_________ your knee while running?

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