管道直径d=10mm，通过流量Q=20cm3/s，运动粘度=0.0101cm2/s 。管中水流流速为（）。 ["255.0","2.55","0.255","25.5"]
中肾
You have a computer that runs Windows Vista. You connect to your company’s network by using a virtual private network (VPN) connection. You notice that when you establish the VPN connection, you are unable to access Internet Web sites. When you disconnect the VPN connection, you can access Internet Web sites. You need to access Internet Web sites while you are connected to the VPN connection. What should you do?（） ["A","B","C","D"]
密码学历史上第一个广泛应用于商用数据保密的密码算法是（）。 ["AES","DES","IDEA","RC6"]
闭合流域与非闭合流域之间的区别，主要在于（）。 ["流域内河流河床下切的深度不同","流域的地面分水线与地下分水线在平面位置上是否重合","流域径流量中是否包括地下径流量"]
屏护装置应与哪些安全措施配合使用？
