He is doing special exercises to strengthen his depressor muscle.

Primitive communism is one of the initial forms of human social organization.

The system of provinces was a part of the ancient political system in Japan.

Let's cherish every encounter with the spirit of 'once in a lifetime'.

Life is a series of ups and downs.

He does his work perfectly, dotting the i's and crossing the t's.

I conducted an interview in a question-and-answer format.

She was a secret kunoichi (female ninja).

He threw a handful of sand into the sea.

"Once in a lifetime" means to cherish the encounter that happens only once in one's lifetime.