对某人提供的帮助表示感谢，感谢信。
dear xx:
一．i am xxx staying in xxx for nearly six months and now i xxx.
in this letter i would like to convey/show/express my heartfelt appreciation to you for your kind assistance in xx when i xxx.
二． xxx
三． in addition, your generous help and tender care made me feel xxx. (and that kindness impressed me with an unforgettable experience.) anyway, thank you sincerely.