This library is a treasury of knowledge.

This bog has been a natural treasure trove since ancient times.

Once upon a time, there was a big castle in this place.

Once, we used to play in the park every day.

In the past, we used to play in the park every day.

He tends to hold onto past failures.

I love nature.

This park is very rich in nature.

He naturally demonstrated leadership.

Mr. Kamayatsu is my best friend.