The passenger pigeon is an extinct species that was once very common in North America.

My dream is to time travel.

We will hold a meeting to make a new business plan.

Tomorrow's flight has been cancelled as planned.

Tomorrow's flight has been cancelled as planned.

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

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.

Please remember to bring your travel documents.