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Commas, Dashes & Parentheses

go to dashes and parentheses

Commas

Commas are probably the most commonly used punctuation marks. However, they are also probably the most commonly misused. Commas are appropriate in the following situations:

1. To separate independent clauses joined by coordinating conjunctions (and, but, or, nor, and for):

Example: I ordered a chocolate ice-cream cone, and my sister ordered a butter pecan.

NOTE: If you do not have a coordination conjunction between the two main clauses, a comma will not suffice. Use a semi-colon between independent clauses not joined by a coordinating conjunction. Alternatively, make two sentences.

2. Commas separate introductory elements from independent clauses that follow. These may be words, phrases, or dependent clauses:

Example: Unfortunately, we forgot to check the oil before we left for Canada.

NOTE: Very short introductory prepositional phrases DO NOT need commas, but longer ones do.

Examples:

During the night we lost power.
Just at the height of the thunderstorm, we lost our electricity.

3. Commas separate items in a series:

Examples:

The child was allergic to nuts, cheese, and corn.
She talked, Sarah listened, and Caleb looked out the window.

4. Commas separate non-restrictive elements from the rest of the sentence. (Non-restrictive denotes elements which are not necessary to the basic meaning of the sentence)

Examples:

The professor who is speaking wrote the article in question.
The poet, who had traveled through six cities before this one, finally arrived.

In the first sentence above, the clause is restrictive because it specifies which particular professor. The clause in the second sentence is non-restrictive because if it were omitted, the sentence would still be a complete thought.

NOTE: Clauses introduced by who or which are sometimes restrictive and sometimes not. Clauses introduced by 'that' are always restrictive (no comma).

5. Commas can be used in some other random ways:

to separate items in dates, addresses, numbers, etc.
commas follow years, states, and countries when they occur in the middle of sentences as parts of dates and locations (I received a letter from London, England, about my internship.)
commas separate contrasting elements introduced by not, but, or yet.
commas separate coordinate adjectives (adjectives of equal importance in a sentence)

Example: She wore a bright, bold plaid.

IN GENERAL, if you could reverse the order of the adjectives or separate the adjectives with the word 'and,' a comma is correct.
Commas separate echoing questions at the end of sentences. (I love the ocean, don't you?)
Commas separate nouns of address. (Sue, when can I sign up for an appointment?)
Commas separate denotations of speaker from direct quotations. ("I'm too busy to play rugby today," she explained.)

6. Do not use commas:

between subjects and verbs or between verbs and objects.
between words or phrases joined by coordinating conjunctions (but you do use them between independent clauses joined by coordinating conjunctions.)
too many times in one sentence. This usually indicates too many modifiers or poor use of prepositional phrases.

Dashes

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Dashes are used in most of the same ways as commas. The chief difference is that a dash calls for a longer voice pause. To type a dash, type two hyphens (--). REMEMBER that the hyphen is a spelling mark, not a mark of punctuation. Also, dashes do not require space before or after them.

Use dashes:

to set off a parenthetic element that is especially emphatic
or has commas of its own
or is a sentence by itself

Example: For some reason--it's weird, isn't it?--I can never remember her name.

to set off afterthoughts

Example: Astronomy and astrology are often confused--like religion and occultism.

to introduce an explanation or explanatory series. (Usually this is the place for a colon, but a dash can be more informal)

Example: There are two major divisions of feminism--equality feminism and gender feminism.

Parentheses