Having nightmares before exams is a sign of your stress. As the saying goes, I miss the exam too much during the day. Sleep at night and have related dreams. Therefore, we must adjust our mentality, especially when the big exam is coming, and we must not let ourselves have too much psychological pressure, which will be counterproductive and affect the effect of review. It's hard to do well in the natural examination.
You can take a walk in the park to relax. Let yourself reach your best, so that you can get good grades in the exam.