1. I am grateful / obliged to you for …

　　我非常感谢你的……

　　2. I am greatly indebted to you for what you have done.

　　我为你所做的一切表示感激。

　　3. I am thankful / obliged to you for your unselfish assistance during …

　　感谢你在……期间给予我无私的帮助。

　　4. I deeply appreciate your courtesy and we hope to have the opportunity of rewarding you rendered me.

　　我非常感谢你的好意，并希望有机会回报你。

　　5. I take this opportunity to express my deep appreciation of your kind help you rendered me.

　　我借此机会对你所给予我的帮助表示深深的感谢。

　　6. It was kind and generous of you to do this for me, and I appreciate it more than I can say.

　　你为我这样做真是太好了，我感激不尽。

　　7. My appreciation to you for your generous help is beyond my words. I wish I could repay it some day.

　　我无法用语言来表达对你的感激之情。但愿有朝一日能回报你的帮助。

　　8. Please accept my most cordial thanks for your timely help, which I will never forget.

　　请接受我诚挚的谢意，感谢你及时的帮助，我将难以忘怀。

　　9. Words fail me when I want to express my gratitude to you.

　　感激之情难以言表。

　　10. Again, I would like to express our warm thanks to you.

　　我再次向你表示感谢。