Main Clauses

Use a comma before and, but, or, nor, for, yet when they join main clauses unless the clauses are very short.

Saturday’s Council meeting was unusually productive, for no one raised any objections.

The first two acts were slow moving, but the third act was full of action and suspense.

You go ahead and I'II follow, [main clauses too short to require punctuation]

When the conjunction joins two verbs, not two main clauses, a comma is not necessary.

I gave some good advice to Gerald and got some from him in return.

(The conjunction joins the verbs “gave” and “got”.)

I gave some good advice to Gerald, and he gave me some in return.

(The conjunction joins two main clauses.)

Many writers use the comma before these conjunctions – as they use the comma before and between the last two items in a series – only when necessary to keep the meaning clear.

NOT CLEAR: I grabbed the dog and the woodchuck limped away.

CLEAR: I grabbed the Jog, and the woodchuck limped away.

As you can see from the preceding examples, a reader may easily be confused if the comma is omitted.

This is especially true of the comma before the conjunction “or”, which should always be preceded by a comma when it means.

Introductory Clauses and Phrases

A comma should be used after an introductory adverb clause, an introductory participial phrase, or a succession of introductory prepositional phrases.

Adverb Clause

While Mario put the costume on, his accompanist played Deep Purple. An adverbial clause at the end of a sentence is not usually set off.

His accompanist played “Deep Purple” while Mario put the costume on.

Participal Phrases

Watching the game from his elm-tree vantage point, Elmer forgot to hold on.

A verbal noun ending in – ing and used as the subject of the sentence should not be confused with an introductory participial phrase.

Washing and polishing the car is fun. (verbal nouns as subject)

Washing and polishing the car, I developed some sore muscles. (participial phrase)

Succession of Prepositional Phrases

At the edge of the deep woods near Lakeville in Cumberland County, he built a small log cabin.

A single introductory prepositional phrase need not be followed by a comma unless it is parenthetical (by the way, on the contrary, etc) or necessary to prevent confusion.

With the weak, competition is unpopular. In the morning I am never wide awake.

PUNCTUATION

Period

1. Use a period at the end of a simple declarative sentence.

The essays were all finished early.

1. Use a period at the end of a polite request.

Please finish your compositions on time.

1. Use a period after a mild request.

Notice the absence of fresh air in this room.

1. Use a period after an indirect question.

They asked if the professor would appear that day.

1. Use a period with most abbreviations.

Dr. Mr. Mrs. Ms. St. asst. (these are used before names)

M.D. D.D. Jr. Sr. Ph.D. Esq. (Do not use a period for abbreviations for agencies or acronyms)

NAACP NATO NAFTA MLA

1. Use periods in parenthetical references and in Works Cited and Bibliographies. See examples on MLA sheet.
2. Use periods with decimals, fractions and fractional amounts of money. Write money with cents in figures not in words.

$4.95