单项选择题
Virtual Private Networks(VPN) are networks deployed on a ( ) network infrastructure.areaD、wide area
单项选择题 You may keep the book ( ) you like.well asB、as long asC、as soon asD、as far as
单项选择题 Which of the following is not the e-commerce business models?
单项选择题 The standard protocol used for sending Internet e-mail is called ( ). It works in conjunction with POP servers.
