通常在回覆英文電子郵件或信件的時候，總是會在開始說明主題之前加入幾句開場白，這時候「謝謝你的回覆」就是非常好的選擇，除了實用，很多情境下使用也不突兀!

謝謝您的回覆

1. Thanks for your reply. / Thanks for your response.

2. Thank you for your reply. 
   
   

3. I appreciate your message.

4. I was so pleased to hear from you.

5. Thank you so much for responding to my email.

6. Thanks for getting back to me.

7. Thank you for contacting us.
8. Thank you for your attention to this matter. 

以下兩句，用於兩人的書信往來討論比較具體的事情時，對方給予回應和新的進度，適合用situation 和issue來代指事情，用updated information來形容對方所回覆的內容是更新的消息及資訊。

1. Thanks for the update on the situation/issue.

2. Thanks for the updated information.

3. Thank you for raising your concerns.
   
   
4. Thank you for your kind cooperation. 

謝謝您的迅速回覆

1. Thank you for your swift response to my e-mail. / Thanks for your swift response.

2. Thank you for the prompt reply. / Thanks for the prompt reply.

3. Thank you so much for the speedy reply.

4. Thank you for the quick reply. / Thank you for your quick response.

5. I am very thankful that you reply me quickly.

有沒有發現上面的規律，其實主要分成兩個部分，一個是謝謝，加上回信這件事情，按照謝謝的說法去替換，有Thanks,Thank you,appreciate,thankful等等用法；而回信也可以用reply,e-mail,response,message等等。

透過這些替換就可以不斷地變化句子，所以一句簡單的「謝謝您的回覆」就有各種不同的說法。

再透過形容詞和副詞的使用，可以更表達出不同程度的感謝，例如迅速回覆，可以用prompt,speedy,quickly等來形容，讓句子按照你的情境變換，下一次只要掌握關鍵字，就可以順利地向對方表達感謝回覆啦!

格式：【謝謝（Thanks/ Thank you/ I appreciate/ I am thankful）＋形容詞（prompt, speedy, quickly, swift）＋回信（response, reply, e-mall, message)】

不過，要注意的是，當你變換不同的單字或詞性時，要記得確認文法是否正確，介係詞的有無，才不會求好心切反而寫錯囉!

參考資料:

http://www.learnersdictionary.com/qa/how-to-thank-someone-for-a-quick-reply

https://www.quora.com/How-do-you-thank-someone-for-a-quick-reply

https://forum.wordreference.com/threads/i-appreciate-your-prompt-reply.2025694/