core bit

例句：

1. 1. The core bit of the story is about the protagonist's journey.
   这个故事的核心部分是关于主人公的旅程。
2. 2. The company's core business is manufacturing electronics.
   公司的主营业务是制造电子产品。
3. 3. The project's core bit was to improve efficiency in production.
   该项目的核心部分是提高生产效率。