You have to ask him the specific reason for this. He can't hear clearly. There are three reasons. One is that the seat is far from the teacher, so he can't hear clearly. You can talk to the teacher about changing places. One is that children may have problems with their own ears. This needs to go to the hospital for examination. My suggestion is to look at both Chinese medicine and western medicine. The third is that children may not understand what the teacher says, just like a physicist telling a politician advanced physical knowledge, so he feels that he can't hear clearly. This requires you to find a tutor to help him make up lessons. You have to find this specific reason for yourself. I am too far away to help. As for self-examination, just find a room casually or test it in their classroom after school. If you can't hear clearly, there is something wrong with your hearing. Of course, it is also possible that the child is not focused in class, can't understand or can't hear clearly. You can also take your child to a blood test to see if the blood lead content exceeds the standard.