你好，
感谢你邀请我去地方游玩，在那里我玩的很愉快。
我是昨天和家人一起去的，那里有清澈的河水、有蔚蓝的天空，有各种各样绿色的植被，那里的景色是非常美丽，看到这么漂亮地方，让我的的心情很愉快，人也轻松了很多。
再次向你表示感谢，同时，我为你准备的一份小礼物，希望你能收下并喜欢。
Dear ，(左起顶格) (正文，开头空四格)
Thank you for inviting us to ，we had a really good/great time there. It was a good memory in our mind.
My family and I went there yesterday. There were limpid water and blue sky，and lots of kinds of green vegetation. The scenery there was just wonderful and brilliant. Seeing such a beautiful place made us so happy that we felt much more relaxed.
Thank you for your invitation again. Meanwhile I have a little gift for you，I hope you accept it and like it.
Sincerely yours
Eric
(右下，包括敬语和落款)