The wolf lives alone in the forest.

He was sustaining himself with local cuisine during his trip.

I'm scared of growing old.

An old person was walking in the park.

My grandfather is being seen by a specialist in geriatric medicine.

I think waste is an act of economic suicide.

Tetsuro is my best friend.

Ryuichiro is my best friend.

He is working hard to support his family.

He is known as an expert in gerontology.