单项选择题 Your network contains an Active Directory domain named contoso.com. The domain contains a member server named Server1. Server1 runs Windows Server 2012 R2 and has the File and Storage Services server role installed. On Server1, you create a share named Documents. You need to ensure that users can recover files that they accidently delete from Documents. What should you do?（）

单项选择题 You have a network printer connected to print server. You need to be able to print if print server goes down. What should you configure?（）

单项选择题 Your network contains an Active Directory domain named contoso.com. The domain contains a member server named Server1. Server1 runs Windows Server 2012 R2 and has the Hyper-V server role installed. You create an external virtual switch named Switch1. Switch1 has the following configurations: Connection type: External network Single-root I/O virtualization (SR-IOV): Enabled Ten virtual machines connect to Switch1. You need to ensure that all of the virtual machines that connect to Switch1 are isolated from the external network and can connect to each other only. The solution must minimize network downtime for the virtual machines. What should you do?（）