第17题: [单项选择]SQL Server 2000提供了很多预定义的角色，下述关于public角色说法正确的是______。 A. 它是系统提供的服务器级的角色，管理员可以在其中添加和删除成员 B. 它是系统提供的数据库级的角色，管理员可以在其中添加和删除成员 C. 它是系统提供的服务器级的角色，管理员可以对其进行授权 D. 它是系统提供的数据库级的角色，管理员可以对其进行授权 参考答案:D 答案解析:[解析] public角色是系统提供的数据库级的角色，管理员可以对其进行授权，但不可以在其中添加和删除成员，因此答案为D。
Do you know how cities began
Long ago, the world had only a few thousand people. These people moved from place to place, hunting animals for food. No one knows how or when these people learned about growing food. But when they did, their lives changed. They began to live near one another. And so the first villages grew. Many people came to work in the villages. The villages grew very big. From there the cities began.
When machines came along, life in the villages changed again. Factories were built. More and more people lived near the factories. The cities grew very big.
