I only regret that, due to prior commitments, I cannot be with you in person.

我唯一遗憾的是，由于已有约定在先，我不能分身与会。

youdao

To my regret I cannot accept your invitation.

遗憾的是，我不能接受你的邀请。

youdao

I cannot express my sorrow and regret.

我无法用语言表达我的悲伤和懊悔。

youdao

But, across the United States, every day, thousands of women who have taken the bold step to ask for help, are being turned away with regret by domestic violence service agencies that cannot handle the demand for services.

FORBES: Domestic Violence: The Awareness We Overlook

But even Day-Lewis, for all his flair and cunning, cannot spice the proceedings with much joy, and we are left with a hymn to regret.

NEWYORKER: Nine

Politicians cannot help themselves: they talk to their supporters and often say things they may later regret, especially in what they believe are private fund-raisers where they can speak their minds and try to convince their donors that they fervently embrace their causes.

FORBES: The Romney Video: Whoever Shot It Broke The Law in Florida