Apostrophe usage

I understand how to use the apostrophe in cases such as "it's", "don't", "she'll", etc. What I want to know is if you can use it for nouns?

e.g. The cat's on the mat = the cat is on the mat
or My job's really demanding = my job is really demanding.

Great question! Yes you can use contractions (apostrophes) with nouns.

The thing to remember is that we do not usually use contractions in written English. It is very common to say the cat's fat when we speak but generally we would use the full version when we write.

That being said, you can use apostrohes with nouns (when you are contracting).

John's on the phone right now.
Susan's finishing her homework.
Jason's away on business.
The cat's sleeping on the floor.