Pm Going to Buy the Brooklyn Bridge Teaching Objectives grasp the main idea(the belief in superwomen encourages average women to achieve their goals)and the structure of the text 2) appreciate how the author achieves coherence for her essay 3master the key language points and grammatical structures in the text

Teaching Objectives 1)understand the main idea(despite the many negative effects of virtual life the author prefers it to real life) and the structure of the text(contrast between virtual life and real life); -2)learn some rules of interpreting new vocabulary

1. understand the main idea (despite his wealth, Sam Walton remains down-home and devoted to his team) and the structure of the text; 2. appreciate the use of indirect description in portraying person: 3. grasp the key language points and grammatical structures in the text

Text A All the Cab Had Was a Letter Part 1 Objectives Part 2 Cultural Notes Part 3 Text Structure Part 4 Language Points Part Content Questions

Part 1 Objectives Part 2 Background Part 3 Text Organization Part 4 Structure Study Part 5 Language Points Part Translation

Part 1 Objectives Part 2 Discussion Part 3 Background Part 4 Structure Study Part 5 Language points Part 6 Content Questions

Text A Public Attitudes toward Science Part 1 Objectives Part 2 Cultural Notes Part 3 Text Structure Part 4 Language Points Part 5 Content Questions

数据库中的数据是否具备正确、相容关系到数 据库系统能否真实地反映现实世界因此维护数 据库的完整性是非常重要的

保证数据一致性是对数据库的最基本的要求。数据库 的重要特征是它能为多个用户提供数据共享。因此 DBMS必须提供并发控制机制来保证数据库的一致性。 数据库的并发控制以事务为单位通常使用封锁技 术实现并发控制。 本章介绍两类最常用的封锁和三级封锁协议。不同 的封锁和不同级别的封锁协议所提供的系统一致性保证 是不同的,提供数据共享度也是不同的

关系数据库系统是本书的重点。在数据库发 展的历史上,最重要的成就是关系模型。 关系数据库系统与非关系数据库系统的区别 是:关系系统只有“表”这一种数据结构;而非 关系数据库系统还有其他数据结构,对这些数据 结构有其他的操作。 本章讲解关系数据库的重要概念,包括关系 模型的数据结构、关系的完整性以及关系操作。 介绍用代数方式来表达的关系语言即关系代数