Nitric acid is a chemical substance with strong acidity.

Chemotransmitters play an important role in the transmission of information between nerve cells.

The acidity of this lemon is very strong.

He was holding my hand tightly.

He was running while holding a bag.

He always carries an umbrella around.

He is majoring in chemistry at university.

What is this material made of?

This tree is very hard.

He chose that method against his will.