Punctuation Made Painless: How to use a comma (Part 3)

5. Using a comma with direct address

You should use a comma to set off the words stating to whom a remark is addressed.

Johnny, kill the grandpa!

6. Using a comma with parenthetical expressions

A parenthetical expression is an extra piece of information that you can add to your sentence without modifying the original grammar or meaning.

You can lose a parenthetical, and the essential meaning will stay the same.

Separate a parenthetical with a comma:

Clowns, as most researchers know, taste funny. Therefore, cannibals do not eat clowns.

Dogs, unlike cats, have masters. Cats, however, have servants.

However, see the IMPORTANT NOTE below.

7. Using a comma with appositives

An appositive is a word or a phrase that renames the subject.

Separate an appositive with a comma:

Clowns, those sweaty artists, taste funny. Therefore, cannibals do not eat clowns.

Dogs, the humans' best friends, have masters. Cats, those arrogant creatures, have servants.

However, see the IMPORTANT NOTE below.

8. Using a comma for contrast

You should use a comma to show contrast between the sentence parts.

Cats have servants, not masters.

Dogs have masters, not servants.

IMPORTANT NOTE

Generally, if you use parenthetical expressions and appositives, you make your text less readable. You should avoid adding extra information between your subjects and your verbs because a clear sentence require a subject and a verb as close as possible.

In case of parenthetical expressions, consider starting your sentences with them:

In case of appositives - have them in a separate clause:

See Part 1 of "How to use a comma" here.

See Part 2 of "How to use a comma" here.