单项选择题 在二进制数字调制中，载波的幅度、频率和相位只有（）变化状态。

未知题型 Your network consists of numerous domains within a LAN, plus one remote location that is configured as another domain within the tree. Each domain contains several organizational units. The remote domain is connected to the main office network by using 56-Kbps connection, as shown in the Exhibit.The remote location is running a previous service pack for Windows 2000, and the LAN is running the most recent service pack.You want to configure a group policy for the remote location so that users can repair a problem with a service pack system file. You also want to reduce the traffic on the LAN and ease administration of the group policies. You want to retain the domain administrator's access to the group policy configuration.What should you do?

多项选择题 关于触发器，哪三句是正确的（）