Read the letter and choose the words/phrases which are more polite and respectful

Dear Mr. and Mrs. Smith,

[I thought I'd drop you a line|I am writing to you to][thank you both very much|say thanks] for having let me stay with you. It was a great experience which I will always remember.

[ I really appreciate your efforts.|You two were great! ] Both of you made me feel like I was part of the family. My room was very comfortable and the home-cooked meals were delicious. I never thought I would have such a pleasant and memorable stay.

[Also|Anyway], living at your house over the summer months helped me a great deal with my language course. It gave me a chance to practise my English outside of the classroom.

[It is for this reason that|That's why]I have improved so much in such a short period of time. [Thank you once again|Again, thanks] for all your kindness. [My parents also send their regards|Mum and Dad also say hi] and would like you to know that you [can drop by|are welcome guests] whenever you visit our country. I would love to hear from you whenever you have time to write.

[Best wishes|Lots of love],

Ludmila