THE CHOICE OF TOPICS IN MALE, FEMALE AND MIXED-SEX GROUPS OF STUDENTS OF PETRA CHRISTIAN UNIVERSITY IN THEIR CHATTING - Nugroho, Aylanda Dwi; Shierly Agustin|English Department, Faculty of Letters, Petra Christian University,|Surabaya-Indonesia|e-mail: aylanda@peter.petra.ac.id (Institute of Research and Community Outreach - Petra Christian University, 2005)