对考试的担忧一直在折磨着她。

The fear of exams was ___preying on her constantly.

这只狐狸正在捕食田野里的兔子。

The fox is ___preying on rabbits in the field.

这些骗子专门针对孤独的老人下手。

These fraudsters are ___preying on lonely elderly people.