My grandmother is being seen by a specialist in geriatrics.

He is a specialist in that field.

He is known as an expert in gerontology.

My grandmother is very kind.

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

He is known as an expert in gerontology.

My grandfather is interested in gerontology.

He decided to start his own business, waiting for the right opportunity.

He decided to watch the stars all night long.

After listening to her story, I cried in sympathy.