同学你好，该知识点来自沪江网校《新概念英语第二册【随到随学班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
以下写法供你参考：

Thank you for your kind invitation to the party.
What a surprise to hear from you after all these years!
Forgive me for not responding to your last letter sooner.
I have no idea how to thank you for your generous gift.
I am sorry to hear about the loss of your pet.
It was very thoughtful of you to send me a birthday card.

祝同学学习进步~