In expository prose, paragraphs can (and should) be neat and utilitarian.

写说明文时候，落可以（并是）简洁实用。

It's only a single sentence long, and expository paragraphs almost never consist of a single sentence.

这话只由一句，陈述解释落几乎绝少只由一个句子构成。

The ideal expository graf contains a topic sentence followed by others which explain or amplify the first.

理想说明落以概括句子起头，接下去句子解释或者详述第一句内容。

This article is a piece of expository writing.

这篇文章是一篇说明文。