一道填空题,到底用doing还是to do?

问题描述:

一道填空题,到底用doing还是to do?
I shoud say sorry to Kate.I regret _____(refuse) to help her that day.

REFUSING REGRET TO DO是很遗憾地要做某事.比如I REGRET TO SAY..我很遗憾的要对你说.REGRET DOING是很遗憾做过某事.比如I regret having broken your window.我很遗憾把你窗户给打破了 句子中THAT DAY表示是以前的...