His story made me associate with old memories in my mind.

He went to the gym for five days in a row.

This issue is closely related to his research.

I practice the piano every day.

He is said to be the most famous alchemist in the world.

He is interested in ancient alchemy.

He conducted a series of experiments.

Pyramid schemes are prohibited by law.

The ecosystem of this lake heavily depends on a specific food chain.

The food chain of this forest is very complex.