通常以哪一种最常见（重要）？
You need to design a Windows Server Update Services （WSUS） infrastructure that meets the following requirements： èThe updates must be distributed from a central location. èAll computers must continue to receive updates in the event that a server fails. What should you include in your design？（） ["Configure two WSUS servers in a Microsoft SQL Server 2008 failover cluster. Configure each WSUS server to use a local database.","Configure a single WSUS server to use multiple downstream servers. Configure each WSUS server touse a RAID 1 mirror and a local database.","Configure a single WSUS server to use multiple downstream servers. Configure each WSUS server to use a RAID 5 array and a local database.","Configure a Microsoft SQL Server 2008 failover cluster. Configure two WSUS servers in a Network Load Balancing cluster. Configure WSUS to use the remote SQL Server 2008 database instance."]
中共十八届四中全会提出，法律的权威源自（）。 ["A、人民的内心拥护和真诚信仰 ","B、科学立法 ","C、依宪执政 ","D、司法公正"]
填写下列表格中空白的部分。
保险合同成立与保险合同生效的关系是（） ["前者是后者的前提条件","后者是前者的前提条件","二者互为前提条件","二者并无实质关系"]
电能生产的特点是什么？
