Model Answer:
Dear John,
I hope things are going well. The reason I am writing is that I have just received the photos you sent.

To begin with, allow me to express my gratitude, the photographs reminded me of the good times and I wanted to thank you for the vacation and the pictorial memories.  I really appreciate the time you devoted to taking me around and your great hospitality.

I was not able to write to you earlier as I have been frantically busy with work since the moment I came back to the office. To be honest, I have to bring work home every day, so that I can finish it before the deadline.

Additionally, I would like to extend an invitation for you to be my guest. I remember you said that you needed a vacation and it would please me greatly if you can come to Thailand as there are many things I would like to show you. Of course, you must stay at our house during the vacation.

Thanks again for your photos and let me know if you decide to come here.
Best regards,
Tim
[189 words]

 Task Analysis:
Who will receive the letter: family member
Relationship: family
Formality level: informal

 Language:
THANKING SOMEONE:
Thank you very much.
Thank you kindly.
I can’t thank you enough.
No words can express my gratitude.
I am extremely grateful for…
I very much appreciate your ______ing …

APOLOGIZING:
I’m sorry about…
I am sorry that…
I’m very sorry about…
I’m very sorry for…
Please forgive me for…
I’d like to apologize for…
Please accept my apologies.
Please accept my sincere apologies. (very formal)

INVITING SOMEONE:
I would like to invite you …
Please come to my…
If you have time I would love to visit me …
Please join us next week…
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