gǎn xiè
感谢信丨再三感谢
gǎnxièxìn | zàisān gǎnxiè
Thank you letter | Thanks again and again
我很感谢他的热情帮助。
wǒ hěn gǎnxiè tā de rèqíng bāngzhù.
I am very grateful for his enthusiastic help.