He is fifty years old and still full of energy.

My birthday is on the fifteenth.

In chemistry class, I learned about the process of polymerization.

Through this chemical reaction, monomers polymerize to form polymers.

My room is twenty-five square meters.

Doublet is an important concept in linguistics.

During the war, he continued to support his family on the home front.

He always ends up losing out to others.

He has the ability to understand human speech.

He was surrounded by his family when he was on his deathbed.