回答

・It was a great help.
・It's all thanks to you.

「多虧有你，幫了我大忙」用英語可以說 It was a great help. 或 It's all thanks to you. 。

Thank you for the other day. It was a great help. Please let me know if you have any problems.
（謝謝你那天的幫助。 多虧有你，幫了我大忙。 如果你有任何問題，請告訴我。）

Thank you for your help. It's all thanks to you. I'll treat you to lunch next time.
（謝謝你的幫助。 多虧有你，幫了我大忙。下次我會請你吃午餐。）

以上回答，供您參考。

有幫助｜0