C. Help Peter write a short reply to Tina by completing the message.
Hi Tina,
I'm sorry 1. (你不能来参加聚会).
Thank you for 2. (在聚会细节方面提供帮助). I hope your party goes well. If you need help with 3. (你的家庭聚会) later, feel free to tell me. I'd love to bring some snacks or help with decorations.
4. (祝你们玩得开心!)
Best wishes,
Peter

1. You can't come to the party 2. offering to help with the party details 3. your family party 4. Have a great time! / Enjoy yourselves!

【分析】这是一道英文书信补全题，需根据中文提示，结合英语的语法规则和固定搭配完成填空。第1空位于“I'm sorry”后，需用宾语从句表达“你不能来参加聚会”；第2空前是“thank you for”，介词后要接动名词，对应“在聚会细节方面提供帮助”；第3空直接翻译“你的家庭聚会”即可；第4空是祝福语，对应“祝你们玩得开心”的常用表达。
【解析】1. “I'm sorry”后可接宾语从句，that可省略，故填You can't come to the party；2. “thank you for”是固定搭配，for为介词，后接动名词，“在聚会细节方面提供帮助”译为offering to help with the party details；3. “你的家庭聚会”直接译为your family party；4. “祝你们玩得开心”常用Have a great time! 或Enjoy yourselves!
【答案】1. You can't come to the party 2. offering to help with the party details 3. your family party 4. Have a great time! / Enjoy yourselves!
【知识点】宾语从句、动名词用法、固定搭配
【点评】本题考查英语书信中的常用表达，涉及基础语法和固定搭配，难度不大，适合巩固英语基础。
【难度系数】0.3