Check you know your question words
One thing students often forget is to study the vocabulary the examiner will use when asking you questions. Listen carefully to the tense that is used in the question as this will guide you in your response.
If you find yourself struggling at any point don't forget, you can say, désóle, je ne comprends pas la question! (Sorry, I don't understand the question!)
After this the examiner should rephrase the question for you in a way you can understand it.
Another helpful phrase is; pardon, est-ce que vous pouvez repéter la question, s'il vous plaît? (Can you repeat the question please?)
