It can be said that I hope this student can face up to his own shortcomings, study hard and make continuous progress. Try to do well in the exam next time.

Example:

1, thank the teacher for educating the children for a long time. Although, this exam, the child's performance is not ideal. We will try our best to cooperate with the teacher's requirements and be strict with the children.

Dear teacher, this is our mistake. Next time, my children will show you with practical actions.

Hello, dear teacher, I didn't do well in this exam. It must be that he didn't pay attention in class and looked around. It's so funny. It will be improved next time. Thank you for your careful teaching. We will study hard.