单项选择题
A．the payment for online services B．the functions of online services C．the development of online services D．the relation between online services and the users
A．seek for a large amount of information B．be connected to various databases C．be introduced by the local library D．pay a monthly membership fee
A．save the time of connecting to the online system B．reduce the risk of losing information C．pay just local telephone charges D．get local information only