Hi there, I had the same problem. I'm a French native speaker and hadn't really done any German since A-level. It was obvious at interview (I went to York) that my German was very rusty so they advised that I take refresher courses and I did conversation with other German speakers on my course. I wouldn't worry too much about it just yet. As long as your first language is good enough you can always get your second language back up to scratch. To answer your question, they asked me a question in German about what I thought about teaching. For first language, the non-native speakers had to do a translation exercise.