感谢同事的万能句：你真是帮了我大忙。

经典表达：

You helped a lot!

你真是帮了我大忙。

举一反三：

Thanks a million.

I really appreciate it.

Thank you from the bottom of my heart.

I cant't thank you enough.

I want to thank you for your kindness to me.

I really appreciate what you've done for me.

I just wanted to tell you how much I appreciate your help the other day.

It's generous of you to take so much interest in my work.

How thankfully I feel for your help.

Without your help I really don't know what I would have done.