He can't be called a casual gamer because he plays games seriously.

He shook his head up and down.

He learned about the concept of Gemeinschaft in his sociology class.

Above heaven and under heaven, his name is known.

The Six-Tusked White Elephant is said to be a legendary creature.

This museum exhibits wonderful artworks collected from all over the world.

Visual arts are a powerful means of expressing human emotions and thoughts.

In chemistry class, I learned about alkanes.

Alkynes play a very important role in organic chemistry.

Alkenes, also known as olefin hydrocarbons, play an important role in organic chemistry.