429. I am writing to extend my sincere gratitude for...

英語四級譯文:
謹以此信表達我對……的真誠感謝。

四級詞匯講解:
本句型是典型的感謝信的開頭。其中，sincere意為“真誠的;誠摯的”。如:
Please give my sincere regards to all the members of your family.請向您全家轉達我真摯的問候。

gratitude意為“感謝的心情”。如:
We owe you a debt of gratitude for your help.承蒙幫助，感激不盡。

本句型中，介詞for后面應該接名詞或者名詞性短語。如:your recommendations(您的推薦)，your attendance in the conference Monday(您出席周一的會議)等。

四級句型拓展:
※ I am writing to express my thanks for your presence on my birthday party.
謹以此信表達我對您參加我生日聚會的感謝。
※ I am writing to show my sincere appreciation for your presence on my birthday party.
謹以此信表達我對您參加我生日聚會的真誠感謝。
※ I feel deeply indebted to you and I really don't know how to thank you enough for your help.
我感覺欠您的太多，真不知道怎樣才能感謝您給予的幫助。