Your second sentence would make more sense to me if you repeated "chapter" rather than replacing "chapter" with "unit".
"Chapters" are not always "units" .
It is equally acceptable, Swarovski.Is it equally acceptable if I use the word "unit" twice?
The twelve-unit textbook was completed. Each unit contained three sections: pre-reading questions, an article, and grammar points.
In other books, "chapters" are not "units".
I'm sorry, Swarovski, but that isn't what I was trying to tell you.So maybe Chapters 1 and 2 constitue a unit; and Chapters 3, 4, and 5 constitute another unit. Is that right?
There is no well-defined, universally-used relationship between chapter, unit, and lesson.So maybe Chapters 1 and 2 constitue a unit; and Chapters 3, 4, and 5 constitute another unit. Is that right?