To inflict harm or damage on someone or something means to make them suffer it.

例如：

Rebels say they have inflicted heavy casualties on government forces.

反叛武装称他们使政府军遭受重创。

介词on 含有“强加于；施加于”之意，让对方不情愿地接受。此句不能用to。

关于on 表示“强加于；施加于” 的例句：

The police used unnecessary violence on the crowd. 警察对群众施加不必要的暴力。

The government imposed export restraints on some products. 政府对某些产品实行出口限制。

She centered her affection on her son.  她把爱集中在儿子身上。

The computer has a great impact on modern life.  计算机对现代生活产生了很大的影响。

How will the war impact on his generation?  战争对他这一代会有什么影响呢?

Punishment had very little effect on him.  惩罚对他没有什么效果。

Don't be too hard on him; he didn't mean to do it.  不要对他太严厉，他并不是故意这么做的。