His room is very simple.

She prefers a simple life.

The Soviet Socialist Republics Union was a country that once existed.

Magnesium is an important mineral for the human body.

The teachings of Jesus Christ have a great impact on our lives.

He is an expert in enzymology and conducts many researches.

Hydrocarbon is a basic element of chemical reactions.

Heavy hydrogen is one of the isotopes of hydrogen.

My great-great-grandmother is still healthy and living a long life.

He has fundamental knowledge of mathematics.