Carlos is my best friend.

The history of the Comintern is very interesting.

String theory is a branch of physics that is a theory for understanding the basic structure of the universe.

He wrote a new paper on string theory.

My new four-wheeled vehicle is very fast.

He is suspected of using a tampered ROM in pachinko.

That joke is hilarious, isn't it?

There are no words to describe that beauty.

He is always grumbling about trivial things, it's really annoying.

Chlorophyll is a compound necessary for plants to perform photosynthesis.