Students can't go when they get married. How can you say that you can politely refuse?

Talk to your classmates first, then talk about your recent life, and then lead the topic to excuses. This excuse can be that your relative is sick (vicious), and you are sick, which makes the other person feel unhappy. Then when the other person comforts you, you say when you will attend his wedding. If the other person is interesting, you will definitely say that you get better first, so you can take the opportunity to say sorry and make it up another day!