He found out the truth and was surprised.

He is really knowledgeable and always teaches us new information.

Assyria was a powerful ancient empire.

I have been to Kunashir.

The sand in this desert is mainly composed of silica.

Gender roles are an important element in defining individual behavior in society.

His role is to fulfill his responsibilities as a leader.

We should save electricity for energy conservation.

We should increase the use of alternative energy to protect the earth.

The potential energy of this ball is large because it is in a high position.