1、forgive sb. sth. 是双宾语，原谅某人某事，侧重于原谅的人，相对于事。
She could not forgive him his infidelities. 她无法对他作出原谅其不忠行为的举动。
I forgave him his crimes. 我饶恕了他的罪行。
2、forgive sb. for sth. 原谅某人（做了）某事， 侧重于原谅事，相对于人。
中的 for sth. 是原因状语，指“由于所犯的错误而原谅某人”或“原谅某人所犯的错误”。常用被动语态 can be forgiven for 表示“某事可得到原谅”.
She could not forgive him for his infidelities.她无法由于他的不忠行为而原谅他本人。
3、forgive sb. for doing 原谅某人做了某事
Please forgive my interrupting. 请原谅我打扰了
She can not forgive you for messing her about.
你对她的粗鲁，她不能原谅你。