词汇： appreciate感激 convey / express one’s appreciation表示感激 cordial衷心的 beyond words难以言表 courtesy礼貌 generosity慷慨 grateful感谢 gratitude感激之情 hospitality好客 moved感动 timely及时的 句型： 1) I take this opportunity to express to you my deep appreciation for the kind assistance you rendered me. 2) I wish there were a better word than “thanks” to express my appreciation for you generous help. 3) My appreciation to you for your generous help is beyond words. I wish I could repay it one day. 4) Please accept my most cordial thanks for your timely help, which I will always remember. 5) Thank you from the bottom of my heart for your kind help.