He has developed a writer's callus on his hand because he writes for long hours every day.

I bought a new tailor's chalk pen.

I drew a picture with a new felt-tip pen.

My new graphics tablet is very easy to use.

My new marking pen is brightly colored.

My new marker pen has vibrant colors.

I used pentane in a chemistry experiment.

What is his pen name?

There is a class observation at my son's school tomorrow.

Organic solvents play an important role in chemical reactions.