主码是一种候选码，主码中的属性个数可以为多个。 正确。 错误。
运行锅炉只使用吸风机来抽烟气的通风方式称为（） 正确。 错误。
Your virtual environment includes Windows Server 2008 R2 Hyper-V servers. You manage the environment by using Microsoft System Center Virtual Machine Manager （VMM） 2008 R2. You are planning to install an application upgrade. Testing the production application requires access to the following three virtual machines （VMs）： a domain controller， a server that runs Microsoft SQL Server， and an IIS Web server. You need to test the application upgrade in a virtual environment that is isolated from the production network. Which two sets of actions should your plan include？（） 正确。 错误。
You are the desktop administrator for your company's sales department. The IT manager for the sales department needs to distribute a custom application to the Windows XP Professional computers in the sales department. He deploys the software by using Group Policy. Susan is a user in the sales department. She reports that the custom application is not available. You examine her computer, and you verify that the application is not present on her computer. You want to ensure that the software is deployed the next time Susan logs on. Which command should you run?（） 正确。 错误。
农业、林业行政主管部门可以委托具有资质的种子质量检验机构对种子质量进行监督检验，并承担检验费用，（）被检验者收取费用。 正确。 错误。
在一个关系R中，若存在X→Y且X不包含Y，则称X→Y为非平凡依赖，否则，若存在X→Y且XY，则称X→Y为平凡依赖。
