He was deeply involved in the project.

He is deeply involved in the project.

The author's message is written on the opening page of this book.

I live in the Kanto region.

He avoided talking about actual sex acts with her.

His most favorite food is sushi.

He is majoring in mineralogy at university.

Mineral oil is often used in the manufacture of cosmetics and pharmaceuticals.

This structure was built centuries ago.

This area is known for producing a variety of minerals.