Proofreading for Commas
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Compound Sentence Commas
1. Skim your paper, looking only for the seven coordinating conjunctions:
and, nor, but, so, for, or, and yet.
2. Stop at each of these words to see whether there is an independent clause (a complete sentence), on both sides of it. (For more help, see our handout on independent clauses at http://owl.english.purdue.edu/handouts/grammar/g_clause.html.)
3. If so, place a comma before the coordinating conjunction. Examples:
She wanted to buy a new car, but she didn't have enough money to do so.
1. Skim your paper, stopping at every comma.
2. See whether you have an independent clause (a sentence) on both sides of the comma.
3. If so, change the sentence in one of the following ways:
Introductory commas after dependent clauses
1. Skim your paper, looking only at the first two or three words of each sentence.
Other introductory commas
1. Skim your paper, looking only at the first word or two of each sentence.
3. Place a comma at the end of the introductory phrase. Examples:
To get a good grade, you must turn in all your homework problems.
4. If the sentence begins with a prepositional phrase (a phrase beginning with in, at, on, between, with, etc.), place a comma after the prepositional phrase if it is longer than three words or suggests a distinct pause before the main clause. Examples:
On his way to work, Jim stopped for coffee at the diner.
1. Go through the paper, stopping at each comma.
For disruptive commas between compound verbs or objects
1. Skim your paper, stopping only at the coordinating conjunctions: and, or, nor, but, so, for, or, and yet.
For disruptive commas between subjects and verbs
1. Find the subject and verb in each of your sentences.
1. Skim your paper, stopping at the conjunctions.
2. Check to see if these conjunctions link words, phrases, or clauses written in a series.
3. If so, place commas after each word, phrase, or clause in the series (except the last one, as demonstrated in this sentence: no comma after the word clause). Examples:
People who are trying to reduce saturated fat in their diets should avoid eggs, meat, and tropical oils.
Commas with Nonessential Elements
1. Skim your paper, looking for a phrase or clause in each sentence that explains or gives more information about a word or phrase that comes before it. (See also our handout, Commas With Nonessential Elements at http://owl.english.purdue.edu/handouts/grammar/g_commaess.html.)
2. If you can delete the phrase or clause and still keep the meaning, the phrase or clause is probably nonessential and needs two commas, one before and one after (unless the phrase or clause is at the end of the sentence).
3. As an alternate test for a nonessential phrase or clause, try saying "by the way" before it. If that seems appropriate to the meaning, the phrase or clause is probably nonessential. To understand the essential vs. nonessential distinction, compare the following sentences. In the first, the clause who cheat is essential; in the second, the clause who often cheats is nonessential.
Students who cheat only harm themselves.
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