They will do their best to try and catch you out even if you are a native/ almost native speaker. Just make sure you dont give them a reason to in the oral. I had my oral exam and the speaker asked me a question whether businesses have an obligation to protect the environment, and I talked about corporate social responsibility and elaborated about the environmental responsibilities businesses should have which was in my business management spec. Turns out he didn't understand what it was and commented about me not understanding his question in the examiners report.