"First composition" 用英语表达可以是 "first piece of writing" 或 "first written work." 这个短语通常指的是某个人第一次写作的作品。

来源：这个短语是由 "first" 和 "composition" 拼接而成。"First" 意为 "第一个"，"composition" 意为 "作文"。

例句：

My first composition was a short story about a magical unicorn.
(我的第一篇作文是一篇关于魔法独角兽的短篇小说。)
She still has her first composition from when she was in second grade.
(她仍然保留着她在二年级时写的第一篇作文。)
He was proud of his first composition, a poem about love.
(他为自己的第一篇作文感到骄傲，那是一首关于爱的诗歌。)