He is world-famous as an entomologist.

He is a former lawyer who was a prosecutor, and he is making use of that experience.

This is my unused camera.

There is a state-of-the-art incubator in my laboratory.

This old battery is no longer usable.

I mixed the pancake batter with my new whisk.

He is well-versed in the use of hidden weapons.

He analyzed the light of the stars using a new spectroscope.

He spoke to the people at the assembly using a loudspeaker.

If you press this switch, the lights will turn on.