My grandfather used to till his privately-owned rice field.

He holds a personal grudge against me.

Using the private railway makes commuting very convenient.

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.

I'm sorry, but I don't speak Japanese.

I'm a Muslim, so I fast during Ramadan.

I'm Jewish.

She used to be a prostitute, but now she has started a new life.