The shared knowledge logic and conceptual notion of an epistemic community will reach to common policies and promote its practice.

Constructivism provides us with a new approach to study individual cases such as human rights,trade frictions,and arms embargo,in order to analyze the process of building-up shared knowledge and constructing identities and interests through social learning of bilateral interactions.

This paper holds that shared knowledge plays an important role in communication because shared knowledge will affect the choice of information.

The shared knowledge reached at as the result of utterance choice sets confinement on and provides the drive for turning-taking,while allowing for the conversational implicature as "missing links" and "silence" in response turns.