Objects have the property of ______ —although objects may know how to commu- nicate with one another across well-defined interfaces, they normally are not allowed to know how other objects are implemented.

Translate the following paragraph into Chinese. With the development of computer science and the Internet technology, social networking services (SNS) have come to be a widely popular platform to build social networks or social relations among people in recent years. SNS are web-based services that allow individuals to create a public profile, create a list of users with whom to share connection, and view and cross the connections within the system. Social networking sites are varied and they incorporate new information and commu