I regretted to tell you the news.

I regretted to tell you the news.
为什么不是I regretted telling you the news./I regret to tell you the news.
我就是问为什么题目的regret 要加ed.为什么不能是以下的?
I regretted telling you the news.我后悔告诉了你这个消息.
I regret to tell you the news.我很遗憾地要告诉你这个消息.
regret to do后悔要去做某事 "我"还没有去做,怎么能加ed?