He took a deep breath and inhaled the fresh air.

The dual number does not exist in English grammar.

The service life of this machine is 10 years.

I learned about Avogadro's number in chemistry class.

My hobby is playing wind instruments.

He is good at playing the trumpet.

The total number of this class is 30.

Before his afternoon work, he always takes a nap.

I take a nap every afternoon.

The production costs of this project were more than expected.