over-and-over addition

例句：

1. 1. She over-and-over repeated her story to the teacher.
   她一次又一次地向老师复述她的故事。
2. 2.The teacher over-and-over explained the difficult concept to the students.
   老师一次又一次地向学生解释这个难以理解的概念。
3. 3.He over-and-over tried to solve the problem until he finally succeeded.
   他一次又一次地尝试解决这个问题，直到最终成功。