Better sentence-writing in 30 minutes a day - Dianna Campbell 1995

Notes to remember
Using commas to set off phrases
Punctuating sentence combinations

Sometimes it’s a matter of your own judgment whether or not to set off an introductory phrase or an end phrase from an independent clause. You’ll do fine as long as you use this question as your guideline: What will make my sentence easier to read? That, of course, is the whole purpose of punctuation—making your writing easier for your reader to understand.

When a single word or a very short phrase appears before an independent clause, you can usually go either way. For example, you can insert a comma after the introductory phrase in each of these sentences, or you can leave it out:

(a) In a minute she’ll be ready.

(b) Later he’ll stop at the library.

(c) Actually I don’t know what to do.

But there are times when you should definitely use a comma even though you might have only one word before the start of the independent clause. Yes, No, First, Second, and Third are good examples of single words that should be set off with a comma when they appear as the first word in a sentence. Another example is a person’s name when you are addressing that person in a sentence. Add commas to these sentences:

1. No he isn’t scheduled to play tonight.

2. Yes she seems to be the front-runner.

3. First you must have the desire to write well.

4. Second a certain amount of time must be set aside for the effort.

5. Ann come here for a minute.

6. George do you think we’ll have time for a short drive?

When in doubt, try reading aloud and let your reader’s need for a pause be your guide.

Exercise 3.5

Add commas to set off phrases where doing so makes the sentence easier to read. (You might want to label the key structural components of the clauses to make your decisions easier.)

1. In the lingo of the racetrack a maiden is a horse that has not yet won its first race.

2. First awarded in the American Revolution the Purple Heart is bestowed upon soldiers who are wounded in the line of duty.

3. The city of St. Petersburg has undergone something of an identity crisis through the years having been known both as Petrograd and Leningrad.

4. England adopted a national policy of women’s suffrage in 1918 followed by the United States in 1920.

5. The word khaki comes from the Persian word khak meaning “dust.”