He has a very quarrelsome personality.

He gulped down the water, perhaps because he was nervous.

Nice to meet you.

His actions always have a duality.

My room number is two hundred and five.

He defeated the enemy using a two-sword style.

He holds dual citizenship in America and Japan.

I will turn twenty years old next year.

Carbon dioxide is one of the main causes of global warming.

This factory is emitting a large amount of sulfur dioxide.