根据搜索结果，以下是符合要求的英文长句整理：

倒装句与复杂结构

*Not only does this activity broaden our horizon but also enrich our knowledge of traditional Chinese culture. I'm more than delighted to receive your letter, in which you have mentioned that you are interested in our school activity.*

（该句通过倒装结构增强表达效果，同时包含定语从句，符合长难句要求）

经典长句精选

*When you were born, you’re crying but lookers-on were smiling. When you are passing away, you’re smiling but lookers-on are crying.*

（通过对比人生不同阶段的情绪状态，形成强烈反差）

哲理与情感表达

*Love, promised between the fingers, rift, twisted in the love.*

（用象征手法表达爱情中的承诺与裂痕）

*For attractive lips, speak words of kindness. For lovely eyes, seek out the good in people.*

（通过排比句式传递积极的生活态度）

权威语录补充

*Remember what should be remembered, and forget what should be forgotten. Alter what is changeable, and accept what is immutable.*

（简洁而富有哲理，适合书面表达）