问题
填空题
网状、层次数据模型与关系数据模型的最大区别在于表示和实现实体之间的联系的方法：网状、层次数据模型是通过指针链，而关系数据模型是使用 ______ 。
答案
参考答案：二维表
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网状、层次数据模型与关系数据模型的最大区别在于表示和实现实体之间的联系的方法：网状、层次数据模型是通过指针链，而关系数据模型是使用 ______ 。
参考答案：二维表
| 完形填空。 | |||
| It seems that the cities in the future will have to change. Because the world's population __1__ , there will be __2__ people in the cities tomorrow. It may be __3__ for any family to live in a house with land around it. There__4__ enough space for them. __5__ to solve this problem may be the skyscraper city (摩天城). The highest building in the world  today is in Taipei. It's about 509 metres high. The skyscraper cities in the future will be many times __6__ . In a skyscraper city about 250,000 people will live. Nearly a million people can __7__ in four of these great buildings. Each skyscraper city will have four towns in it and each town will have ten villages. They will live, work and __8__ their free time in them. They won't need to leave the city __9__ they want to. They will be able to move about in the city by transport controlled __10__ computers. Let's imagine how the life will be then! | |||
| ( ) 1. A. has grown ( ) 2. A. many ( ) 3. A. impossible ( ) 4 A. aren't ( ) 5. A. A way ( ) 6. A. lower ( ) 7. A. live ( ) 8. A. spend ( ) 9. A. until ( ) 10. A. by | B. is growing B. much B. possible B. won't be B. A road B. shorter B. study B. cost B. when B. at | C. are growing C. more C. important C. won't have C. An answer C. taller C. work C. pay C. while C. with | D. have grown D. larger D. necessary D. haven't D. An idea D. higher D. be D. take D. unless D. in |