那次警告之后，他决定改过自新，专心学业。

After that warning, he decided to ___turn ___over ___a ___new ___leaf and focus on his studies.

她向家人承诺她会改过自新。

She promised her family that she would ___turn ___over ___a ___new ___leaf.

意识到自己的错误后，他决心改过自新，成为一个更有责任感的人。

Realizing his mistakes, he is determined to ___turn ___over ___a ___new ___leaf and become a more responsible person.