单项选择题 After working on a router, some problems arise and you wish to view the commands that you recently entered. Which IOS command opens the history buffer and displays the most recently entered commands?（）

单项选择题 After logging into a router and typing in a few show commands, you press the up arrow key. What will this do?（）

单项选择题 You just purchased a refurbished router that contains a configuration from a previous deployment. What should you do, before entering a new configuration into the router?（）