What do eleven-year-old boys often laugh at in class?

1 1 year-old boy often laughs in class, which shows that he has no class at all and his energy is not concentrated at all. He was thinking about other things, coke, or what game he was watching on TV, so he smiled at the thought. When he smiles, you can remind him to answer questions. He said that he certainly can't answer this question now. I didn't even mention having a good class, so I guided him to concentrate on his studies and don't think about anything else. As long as he studies hard, he won't laugh often.