Note:You're a lucky fellow! I've been surfing the web and found that you need help with english translations. I am a english teacher (america born chinese) and now teaching in an international school. Anyways, here's my answer to your question:
The bell finally rang! I was the first one who dashed from my classroom. On my way home, I came upon Li Si's house, and saw him composing (or writing,compiling--either one) a mesmerizing story with his mother.
(I added some parts that weren't included in your chinese sentence, but it will lightsen up your sentence! In a role of a teacher--me, I hope you will choose my answer, therefore I hope you have an enjoyable english class!:)