sadistic

那个虐待狂老师喜欢看到学生因为考试不及格而痛苦。

The ___sadistic teacher enjoyed seeing his students suffer from failing exams.

那个男孩以sadistic的方式折磨小动物，这让我们都感到非常不安。

The boy tortured small animals in a ___sadistic way, which made us all very uncomfortable.