cruelty 通常用作抽象名词，不可数。如：

I have a deep horror of cruelty. 我对残暴的行为深恶痛绝。

There was a hint of cruelty in Brian’s smile. 布赖恩的微笑里流露出一丝残忍

The state has a law against cruelty to animals. 该州有一项禁止虐待动物的法律。

Cruelty was quite alien to his nature. 残忍的行为与他的本性格格不入。

但若表示具体意义的“残暴的行为”“暴行”，则为可数名词，但通常用复数形式，表示“各种残暴的行为”。如：

The prisoners endured awful cruelties. 囚徒忍受着惨无人道的虐待。

She suffered many cruelties in her short life. 在短暂的一生中她受到许多虑待。

Most other European nations were guilty of equal cruelties. 其他多数欧洲国家都犯有同样的暴行。

He is still haunted by the cruelties he witnessed during the war. 他至今仍被战争期间所目睹的种种暴行折磨着。

The cruelties practised by the fascists, during World War II were beyond description. 第二次世界大战期间法西斯分子所犯之种种暴行罄竹难书。