He can always maintain calmness.

He always remains calm.

This problem can be solved using the principle of linearity.

He believes in eternal life.

I was born in the Heisei era.

Changes in the social system inevitably occur with time.

Feudalism characterized the social system of medieval Europe.

He became distrustful of other people due to his past experiences.

He is involved in the development of androids.

Rumors are spreading throughout the town that he is a werewolf.