问题
填空题
关系操作的特点是 【5】 操作。
答案
参考答案：【5】集合
解析：解析：在关系操作中，所有操作对象与操作结果都是关系。而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。
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关系操作的特点是 【5】 操作。
参考答案：【5】集合
解析：解析：在关系操作中，所有操作对象与操作结果都是关系。而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。
| 阅读短文，选择正确答案。 |
| Tom was a boy. He was six years old. One day, he seated in a restaurant with his father and mother. When they had finished their dinner his father called over the waiter (服务员). "Can I help you, sir?" said the waiter." My son has left quite a lot of meat on his plate." explained his father. "Could you give me a bag, so that I can take it home for the dog." "Great! Dad, have we got a dog?" exclaimed (呼叫) the excited (兴奋的) boy. |
| 1. The story happened (发生在) . |
[ ] |
| A. in the street B. in the restaurant C. in the bookstore |
| 2. How many people are there in Tom's family? |
[ ] |
| A. There are three people in his family. B. There are four people in his family. C. There are five people in his family. |
| 3. After dinner, there was a lot of on Tom's meat. |
[ ] |
| A. milk B. meat C. ice cream |
| 4. Do you think there was a dog in Tom's house? |
[ ] |
| A. Yes, I do. B. No, I don't. C. I don't know. |
每题所给的选项中有一个或一个以上的正确答案。
| 警察甲为了完成上级规定的破案任务，找到特勤乙提供线索。乙没有线索，于是找来丙丁两人，唆使两人抢夺妇女戊。丙丁两人拦路抢劫戊，戊并没有携带任何财物，抢劫过程中造成戊鼻梁骨折，丙在未劫得财物的情况下先行离去，丁后来将戊强 * * 。乙鼓动戊报案，并向甲提供线索，带领甲将丙丁两人抓获。根据上述情况，请回答下列问题。 |
下列说法中正确的是( )。
A．甲如果同意乙将找来丙丁两人进行抢夺，那么甲也要负刑事责任
B．在本案中，乙是唆使犯，所以负主要责任
C．乙并没有犯罪行为，其唆使不是犯罪
D．乙尽管是丙丁的共犯，但没有实施犯罪行为，并且提供重要线索，所以不应当负刑事责任