单项选择题
A. It protected packets of information from being raided. B. It can break everything up into little packets. C. It can meet the world demand of the generic plug-in card.
A. All the devices and parts are put in the basement. B. All the devices and parts are put into a single box. C. Cellular phone and Internet are part of this system.
A. How to control the growing number of intranet users. B. How to prevent teenagers in town from chatting on the Web. C. How to keep some information secret and accessible only to qualified people.