a.Give the definition of "Group" in your own words.

Three or more people work together to accomplish a common goal

b.Discribe the detailed characterictics of the groups.

Interdependence，Common Goal，Group Personality，Commitment，Cohesiveness，Group Conflict，Social Facilitation，Gender Differences，Group Size，Norms

C.How to make the group members get into a positive participation during the group communication?

First of all, every members should be told what are we going to discuss before the meeting， When someone shares his/her point, we should not interrupt or deny.