What do you mean lucky in study and unlucky in exam?

On the surface, it shows that you are still very capable in reading. You may be able to show your profound knowledge in your usual contact and conversation and let others admire you, but you may not perform well in important exams and your grades are not satisfactory. A deeper understanding shows that you haven't mastered the tricks of the exam or have poor psychological quality, so you can't pass the psychological aspects of important exams first. In fact, this is a sign that you are not confident in yourself, and it also shows that your knowledge is wide but not deep. So I hope you can study the content of the exam more deeply, and don't think that a little knowledge is enough.