revision of skin flap

例句：

1. 1. The teacher asked for the students' revision of the lesson.
   老师要求学生复习课程内容。
2. 2. After the exam, I need to revise my notes before going to bed.
   考试后，我需要在睡觉前复习笔记。
3. 3. The book has been revised several times since it was first published.
   这本书自从首次出版以来已经被修订过几次了。