I am an international student in UK, and I did get a quite high mark on IELTS listening, about 8 to 9. And I can easily understand what the professors say in the lecture, partly because I have a quite good academic level in my major and my major doesn't acquire very good English.(I am a pure math major)
However, I can't understand what my classmates are talking about after class. If they are talking to me, things become easier. But when they are making conversation as a group, I simply have no idea what they are talking about. I tried to listen Podcasts and radios, but without sub I can only understand tiny pieces of them. If I return to listen exam-based listening comprehension, they become too easy to me. Thus, I want to know what I can do to improve my listening. I will be very grateful for your help.