This problem falls into the category of mathematics.

This brass vase is very beautiful.

He takes an agnostic stance on religion.

He says 'knowledge is power' and studies hard every day.

Their problem was clearly visible to me, a bystander.

He is making a Rube Goldberg machine at home.

His story, after a caesura, started again.

She chose to have an abortion.

He always lives with the spirit of 'In times of prosperity, do not forget about chaos.'

Acetylcholine is one of the neurotransmitters.