Regret/Gratitude(致歉/致謝)

I'm sorry to hear that. - 聽到這件事我感到難過.
Please forgive me. - 請原諒我.
Sorry, I've made a mistake. - 對不起, 我犯錯了.
It's all my fault. - 全都是我的錯.
Thanks a lot. - 十分多謝.
It's very kind of you. - 你真仁慈 / 謝謝你的好意.
I really appreciate it. - 我真的很感激.
That's all right. - 沒有問題.
You're welcome. - 別客氣.
You've helped me a lot. - 你幫了我不少.
I wish I could help. - 抱歉幫不了你.
I should have warned you. - 我早應該提醒你.
Don't mention it. - 不必客氣.
It's my pleasure. - 我很樂意.
Forget it! - 算了吧!