作用 (zuò yòng): function, role; (to serve as, to play a role)

This medicine has a very good effect on colds.

Water acts to evaporate when heated.

The role of a teacher is to help students learn and grow.

This plant plays an important role in purifying the air.

His suggestion had a great effect on my decision.

This medicine has side effects.

Parents' education has a great effect on children.

He played an important role in the team.

This drug acts on the nervous system.

The new policy has begun to take effect.