This textbook explains mainly in colloquial form.

He is completely nowhere to be seen.

Her necklace was in the beautiful shape of a butterfly.

This sentence is using the inclusive form.

This grammar rule is using the exclusive form.

Exclusive form of grammar is used to refer to a specific object only.

He is the type of person who thinks it's a moonlit night if it's bright, so he only has a one-sided perspective.

He thought deeply and said, 'I think, therefore I am.'

The characteristic of annelids is that their bodies are divided into ring-shaped segments.

This butterfly valve is used to control the flow of fluid.