1. Use a comma in the following situations:
Comma Rules

2. 17a Before a coordinating conjunction joining independent clauses
Examples:
My students love school, and they always arrive on time.
The guitar was very expensive, but I decided to buy it anyway.
A mouse kept trying to take my sandwich so I ran from the restaurant.

3. 17b After an introductory word group
Phrases: Introductory prepositional, participial, and infinitive phrases
Clauses: Introductory Adverb

4. Phrases
A phrase is a group of related words that does not contain both a verb and its subject.

5. Prepositional Phrases
A phrase including a preposition, the object of that preposition, and any modifiers of that object
Around the tree
In the tall, dark tower
Among my many friends

6. 17b
Use a comma to separate an introductory prepositional phrase from the rest of a sentence
Under that giant maple tree, I sat down to read a book.
Before I leave for my date, I should probably take a shower.
Of all the bad movies, this one is surely the worst.

7. Participle A form of a verb used as an adjective. Running Fishing
Flying
Filled
Clogged
Eaten

8. Participial Phrases
A phrase beginning with a participle that also functions as an adjective in a sentence.
Clogged with hair
Eaten by mosquitos
Filled with candy

9. Participial Phrases
The water drained slowly in the pipe clogged with drain hair.
The campers eaten by mosquitos never came back to that lake again.
These baskets filled with candy are the hardest to lift.

10. 17b
Add a comma after a participial phrase before an independent clause.
Clogged with drain hair, the water drained slowly in the pipe.
Eaten by mosquitos, the campers never came back to that lake again.
Filled with candy, these baskets are the hardest to lift.

11. Infinitive phrases
These are phrases consisting of an infinitive (to + a verb) and any objects and modifiers
To smash a spider
To kick a ball past a goal
To understand a difficult book

12. 17b
Use a comma after an infinitive phrase and before an independent clause
To pass your driver’s test, you must study and spend many hours practicing.
To steal the dragon’s treasure, I had to use my magic ring.
To get my oil changed at Midas, I had to wait several hours.

13. Adverb clause
Containing a subject, verb, and subordinating conjunction, these clauses function as adverbs in a sentence.
Until his arms ached
Once they saw her car turn the corner
Whenever my alarm clock goes off

14. Adverb Clauses Tommy scrubbed the bathroom tile until his arms ached.
They knew she was gone forever once they saw her car turn the corner.
My brother screams out loud whenever my alarm clock goes off.

15. 17b Use a comma after an introductory adverb clause.
Until his arms ached, Tommy scrubbed the bathroom tile.
Once they saw her car turn the corner, they knew she was gone forever.
Whenever my alarm clock goes off, my brother screams out loud.

16. 17c Between items in a series
Use a comma between all items in a series, including the last two.
Ex. Bubbles of air, leaves, ferns, bits of wood, and insects are often found trapped in amber.
My goats have eaten corn cobs, aluminum cans, old shoes, and car parts.

17. 17d Between coordinate adjectives
Use a comma between coordinate adjectives, those that each modify a noun separately.
Adjectives are coordinate if they can be connected with ‘and’ and if their order can be changed.

18. 17E– nonessential clauses
Use commas to set off a nonessential clauses– these are clauses that are not essential to the meaning of the sentence.
Remember that adjective clauses always begin with the relative adverbs that, which, who, whose, and whom.

19. 17E – Nonessential clauses
Adjective clauses beginning with which will always be nonessential and must be set off with commas.
The chainsaw, which is in the garage, needs sharpening.
The weed eater, which I haven’t used in weeks, needs new string.
Adjective clauses beginning with that will always be essential, not needing commas.
The lawnmower that I used last week needs an oil change.
The hedge trimmers that we bought at the yard sale are already broken.

20. 17E – Nonessential clauses
Look carefully at clauses beginning with who, whose, and whom to determine whether they are essential and then use commas appropriately.
A student of mine who attended the game said it was a bloodbath.
The author, whom I greatly admire, passed away last year.
The man whose camera I borrowed asked if he could use my mountain bike.

21. 17f
To set off transitional and parenthetical expressions, absolute phrases, and contrasted elements
Transitional expressions – serve as bridges between sentences or parts of sentences. They include conjunctive adverbs such as however, therefore, and moreover and transitional phrases such as for example and as a matter of fact.
*See Hacker p. 62

22. Transitional Expressions
When a transitional expression appears between independent clauses in a sentence, it is preceded by a semicolon and usually followed by a comma.
Minh did not understand our language; moreover, he was unfamiliar with our customs.

23. Transitional Expressions
When transitional expressions appear at the beginning of a sentence or in the middle of an independent clause, it is set off with commas.
In fact, stock values rose after the company’s press release.
Celery, for example, is high in sodium.
Currently, I am a visiting professor at Murray State University.

24. Parenthetical expressions
Expressions that are distinctly parenthetical, interrupting the flow of a sentence, should be set off with commas.

25. Parenthetical Expressions
These are expressions that are parenthetical, interrupting the flow of a sentence. They should be set off with commas. The final example is a parenthetical adverb clause.
Evolution, so far as we know, doesn’t work this way.
Mrs. Veith, in fact, was furious.
Charlie, when he was told about the missing snake, passed out.

26. Absolute Phrases
An absolute phrase combines a noun and a participle with any modifiers.
Legs quivering
Her arms folded across her chest
Our fingers scraping the leftover frosting off the plates

27. Absolute Phrases
Absolute phrases modify an independent clause and are separated from that clause by a comma.
Legs quivering, our old dog Gizmo dreamed of chasing squirrels.
Her arms folded across her chest, Professor Hill warned the class about the dangers of drunk driving.
We devoured Aunt Lenora’s carrot cake, our fingers scraping the leftover frosting off the plates.

28. Contrasted Elements I got a C on a test, not the B I wanted.
Austin writes slowly, but elegantly.
Your essays should be in ink, rather than pencil.
The boy scouts were nervous, yet hopeful.
You should think of education as an opportunity, not a burden.
Your bad grade is due to carelessness, not ignorance.
It was a heart attack, not a stroke, that killed him.

29. 17g
To set off nouns of direct address, the words yes and no, interrogative tags, and mild interjections.
Ex. Brian, did you do your homework?
Yes, the loan will probably be approved.
The film was faithful to the book, wasn’t it?
Well, cases like this are difficult to decide.

30. 17h
To set off direct quotations introduced with expressions such as he said.
Examples:
“You shouldn’t use a power drill on a screw that small,” she said.
Naturalist Arthur Cleveland Bent remarked, “In part, the peregrine declined because it is not adorable.”
“If you’re ready,” his father said, “we can go ahead and pack up the car.”
“Stop it,” I told him. “Nobody thinks you’re funny.”

31. 17i With dates, addresses, titles
Dates: On December 12, 1890, orders were sent out for the arrest of Sitting Bull.
Addresses: Greg lived at 708 Spring Street, Washington, Illinois
Titles: Sandra Barnes, MD, was appointed to the board.

32. Works Cited Hacker, Diana. A Pocket Style Manual:
Fifth Edition. Boston: Bedford/ St.
Martin’s, 2008.