What is your time zone?

He was killing time by reading a book while waiting.

I jog for half an hour every day.

As the time limit approached, I began to panic.

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.

He is the type of person who thinks it's a moonlit night if it's bright, so he only has a one-sided perspective.

He thought deeply and said, 'I think, therefore I am.'