The gerbil lives in desert areas.

This ring uses alexandrite.

Alexandria is a beautiful city in Egypt.

He likes to take a walk in the park at dusk.

He is a perfectionist, so he is very strict about his work.

He played a perfect fifth scale on the piano.

Linear programming is a part of operations research and is used to find the optimal solution.

Paying the urban planning tax is a citizen's duty.

The United Nations Environment Programme is providing solutions to global environmental problems.

Alexander is considered one of the greatest leaders in history.