He was in the garage to repair the car with a rear protrusion.

He was surprised to receive an unexpected phone call.

He suddenly made an unexpected phone call to my house.

He is waiting for someone to call now.

The air in this room is fresh.

What will you use this empty box for?

Looking at the bird flying high in the sky, I felt freedom.

The altitude of this airplane is 10,000 meters.

In mathematics, an empty set refers to a set that does not contain any elements.

I enjoyed a picnic under the clear sky.