设在125ps内传输128个二进制码元，计算信息传输速率为多少？若该信息在5s内有3个码元产生误码，试问其误码率为多少？
You create a Web site that is for members only. The Web site allows members to create lists of users that have access to information about member profiles. The name of the list is stored in the listName variable. The user name of the user to whom access is given is stored in the username variable. You need to enable members to manage their lists of users. Which code segment should you use? （） [" Roles.CreateRole(listName)User.IsInRole(listName)"," Roles.CreateRole(listName)Roles.AddUserToRole(userName, listName)"," Roles.RoleExists(listName)Roles.AddUserToRole(userName, listName)"," Roles.RoleExists(listName)User.IsInRole(listName)"]
孤立病灶
Which of the following statements concerning IGMP are correct？（Choose all that apply.）（） ["With IGMPvl， queries are sent to a specific group","Hosts issuing IGMPvl requests will be correctly interpreted by IGMPv2 hosts due to backwardcompatibility","An IGMPv2 router will ignore IGMPv2 leave messages when IGMFVl hosts are present","With IGMFV2， a leave message is supported","An IGMPv2 host will send an IGMFVl report on an IGMFVl router","An IGMPv2 router can only allow IGMPv2 hosts to execute a join request"]
简述水轮发电机组是如何发电的？
一个国家在激烈的国际竞争中取胜的关键是（）。
