I have an important problem with one of my students in my class. She refuses to work in pairs with some international students in the class and says that she doesn't like people from that country. Should I force her to work with them, or let her work with others in the class as she wishes? By the way, she is about 18 years old, and this is the university prep class. Last week I told her to come and talk to me after class, but she didn't. I really don't know how to deal with it. I talked to my colleagues, but they also don't know what to do.