Use a comma to separate main clauses joined by a coordinating conjunction. The coordinating conjunctions are and, but, or, nor, for, so, and yet. When any one of these conjunctions is used to connect main clauses, it is always preceded by a comma. The comma acts as a signal that one independent clause has ended and the next is about to begin.

Half a million colonists remained loyal to the British Crown during the American Revolution, and for their loyalty many of them lost their homes, property, and livelihood.

History books used to portray Loyalists as conniving aristocrats with British connections, but research has revealed that most were ordinary hard-working farmers and tradespeople.

Loyalists were conservatives who did not want change, nor did they want separation of the colonies from England.

About 36,000 Loyalists eventually emigrated to Nova Scotia in Canada, for this territory was ruled by the British Crown.

Approximately 500,000 of the 2.5 million people in colonial America were Loyalists, so one in every five Americans could be classified as Loyalist.

Nearly 100,000 Loyalist Americans fled the colonies in what was the largest exodus in American history, yet their suffering has largely been unrecognized.

There are, however, two exceptions:

1. Some writers omit the comma before the coordinating conjunction when one or both of the main clauses are very short.

The spirit is willing but the flesh is weak.

2. When one or both of the main clauses joined by a coordinating conjunction are internally punctuated, use a semicolon before the coordinating conjunction.

The Canadian Mounted Police were established in the 1870's to assure peaceful settlement of the northwest wilderness; and they became symbols of political and social order.

However, the trend today is to eliminate the semi-colon and begin the second sentence with the conjunction.

The Mounties, dressed in red tunics and riding well-trained horses, were a familiar sight on the Canadian frontier. But few people in the United States saw Mounties except in the movies.

Use a comma to separate introductory phrases and clauses from a main clause. Introductory phrases and clauses may be adverbial, modifying the verb in the main clause or the whole main clause; or they may serve as adjectives, modifying the subject of the main clause. Whatever their function, they should always be separated from the main clause by a comma unless they are very short and there is no possibility of misreading.


According to legend, Hercules had enormous strength.
After his long exile to France, Charles II returned to England in 1660.


To succeed as a long-distance runner, a person must have strong legs.
Announcing a recess, the judge retired to his chambers.


As soon as she had finished studying, she left the library.
If your job is to write every day, you learn to do it like every other job.

Do not confuse verbal modifiers with verbals used as subjects.

Having been an arbitrator between labor and manage meet for a decade, he felt confident in tackling one more labor dispute.

Use commas to set off nonrestrictive elements. Don't set off restrictive elements. A restrictive element-which may be a clause, a phrase, or a word-is an essential modifier. It defines, limits, or identifies the meaning of whatever it modifies. If it is removed from the sentence, the meaning is changed in some basic way. A nonrestrictive element may be interesting, but it is incidental to the basic meaning of the sentence. An illustration will help to clarify the difference.

RESTRICTIVE         A person who is honest will succeed.
Jacob North, who is honest, will succeed.

In the first sentence the clause who is honest identifies the kind of person who will succeed; it restricts the subject of will succeed to people who are honest as opposed to people who are not honest. In other words, the clause is restrictive. It is thus not set off with commas. In the second sentence, however, the proper noun Jacob North identifies or designates the particular person who will succeed; the fact that Jacob North is honest is merely amplifying information about a person already sufficiently identified. The clause is nonrestrictive. It is set off with commas.

Texans, who have oil wells, can afford high prices.
(All Texans have oil wells and can afford high prices.)

Texans who have oil wells can afford high prices.
(Some Texans have oil wells; only they can afford high prices.)

Always use two commas to set off a nonrestrictive element unless it begins or ends the sentence.

NO   The gate, unlocked and wide-open swung on its hinges.
YES The gate, unlocked and wide-open, swung on its hinges.

OR  Unlocked and wide-open, the gate swung on its hinges.

1. Set off nonrestrictive clauses and phrases with commas.
    Donít set off restrictive clauses and phrases.

Wide porches, which sometimes run along three sides of the house, are called verandas.

Houses that were built in warm climates often featured verandas.

Grandmother's veranda, with its enormous length, was a wonderful place to play
. (Prepositional)

The part with the most meal was filled with wicker furniture.

We children, draping blankets across the furniture, made tunnels and tents.

Anyone wanting to sit on a chair had to dismantle childish hide-outs.

2. Set off nonrestrictive appositives with commas. Donít set off restrictive appositives. An appositive is a noun or a group of words used as a noun that describes or renames another noun, ordinarily the noun that comes immediately before it. Like clauses and phrases, appositives may be either restrictive or nonrestrictive, though appositives of more than one or two words are usually nonrestrictive and therefore set off by commas.

Davy Crockett, the most famous man at the Alamo, was a former Indian fighter.
No treatment, not even hypnosis or acupuncture, helped them stop smoking.

Use commas to set off elements that slightly interrupt the structure of a sentence. Words, phrases, and clauses that slightly interrupt the structure of a sentence are often called parenthetical elements. Although such elements may add to the meaning of the sentence or serve to relate the sentence in which they stand to a preceding sentence or idea, they arenít essential to its grammatical structure. Such elements include words of direct address, mild interjections, the words yes and no, transitional words and expressions, and phrases expressing contrast.

Can you show me, Kathy, how to punctuate this sentence?
Will you speak a little louder, George?

Oh, I never get colds, only sinus infections.

Sales taxes, moreover, hurt poor people severely.
Quakers, on the other hand, are opposed to military service.
The judge ruled, nevertheless, that damages must be paid.
The result, in short, was a complete breakdown of discipline.

He had intended to write 1868, not 1968.
Tractors, unlike horses, require gasoline.
Insecticides and garden sprays now available are effective, yet safe.

Note that other elements of a sentence will interrupt its structure and require commas when theyíre inserted out of their normal grammatical order. Compare the following:

My grandmother always told me that work never killed anyone.
Work, my grandmother always told me, never killed anyone.

The exhausted and thirsty construction workers welcomed the cold beer.
The construction workers, exhausted and thirsty, welcomed the cold beer.

Always use two commas to set off a parenthetical element unless it begins or ends a sentence.

THIS She noticed, however, that tact worked wonders.
She noticed that tact worked wonders, however.

Use commas to separate the items in a series. A series consists of three or more words, phrases, or clauses of equal grammatical rank. The items of such a series are said to be coordinate: they have approximately equal importance. Typical series take the form a, b, and c, or the form a, b, or c.

She talked fluently, wittily, and penetratingly. [Three adverbs]

The triathlon is an athletic event involving swimming, running, and cycling.
[Three nouns]

Only a generation ago, the Navaho were horsemen, nomads, keepers of flocks, painters in sand, weavers of wool, artists in silver, and singers
of the yei-bie-chai. [Seven nouns, some modified by prepositional phrases]

Her sails ripped, her engines dead, and her rudder broken, the vessel drifted helplessly.
[Three phrases]

The city couldn't issue birth certificates on time, pay overtime when it was due, maintain its automotive fleets, deliver asphalt to men filling potholes, submit claims for federal and state aid payments, supply diaper pins to obstetric wards, or hire key staff.
[Seven predicates, each consisting of a verb and its object]

After the accident, the driver of the car had no idea of who he was, where he came from, or how the accident happened. [Three dependent clauses]

Some writers treat three or more short, closely related independent clauses not joined by coordinate conjunctions as a series, separating them by commas rather than semicolons.

Some of the people said the elephant had gone in one direction, some said he had gone in another, some professed not even to have heard of any elephant.

Some writers omit the comma before and in simple a, b, and c series: violins, flutes and cellos; men, women and children. But only if the last two items in the series are related.

I am interested in a modern, furnished apartment with two bed rooms, kitchenette, living room, bathroom with shower, and garage.

Use commas to separate coordinate adjectives in a series. Donít use commas to separate adjectives that are cumulative rather than coordinate. Adjectives in a series are coordinate if each adjective modifies the noun separately. They are cumulative, not coordinate, if any adjective in the series modifies the total concept that follows it.

COORDINATE The British colony of Hong Kong grew up around a beautiful, sheltered, accessible port.

CUMULATIVE Hong Kong is the third-largest international financial center in the world.


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