[填空题] 在任意二叉树中，若有n₀个叶子结点，n₂个度为2的结点，则必有（）。

修改窗体的标题时，应当在属性页中设置的属性是（） ["Caption","Name","Text","Label"] Your company has client computers that run Windows Vista and client computers that run Windows 7.   The client computers connect directly to the Microsoft Update Web site once per week and automatically install all available security updates.  Microsoft releases a security update for Windows 7.   You have the following requirements：   Create a report of all Windows 7 computers that are currently connected to the network and that do not have the security update installed. Use the least amount of administrative effort.  You need to manage the software update process to meet the requirements.   What should you do？（） [" Deploy Microsoft Windows Server Update Services （WSUS）. Approve the security update for installation，and forcea detection cycle on the client computers."," Deploy Microsoft Windows Server Update Services （WSUS）. Approve the security update for detection， and force adetection cycle on the client computers."," Use the Microsoft Baseline Security Analyzer （MBSA） to scan the client computers.Configure MBSA to use the Microsoft Update site catalog."," Use the Microsoft Baseline Configuration Analyzer （MBCA） to scan the client computers."] 液化石油气是在（）加工过程中得到的一种无色挥发性液体。 ["石油","原油","天然气","沼气"] 岩石一般分为三大类即：岩浆岩、（）和变质岩。 ["火山岩","火成岩","水成岩","沉积岩"] 短路是指电路中存在电流绕过部分负载的故障。 在任意二叉树中，若有n₀个叶子结点，n₂个度为2的结点，则必有（）。