纯手工写作如下，确保质量，地道英文，语法正确：

Dear Mr. and Mrs. Johnston,

It has been such a pleasant homestay experience with you and your family during the last two weeks in Australia. I have safely arrived back home.

I would like to thank you for offering me assistance with my winter camp in your country. Without your help I wouldn’t be able to enjoy a trouble-free journey and have tons of fun exploring Australia. Your tips about where to dine, where to shop, and where I should tour around were very useful!

Please do consider visiting my home country as well in the near future and I look forward to becoming your tour guide in China!

Sincerely yours,

Li Hua

记得要采纳满意答案哦~ :-)